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Lomb  Prize  Essay 


11886) 


DISINFECTION  AND  INDIVIDUAL  PROPHYLAXIS 
AGAINST  INFECTIOUS  DISEASES 


American  public  fjcaltl)  Association 


Loa\b  Prize  Essay 


[1886J 


DISINFECTION  AND  INDIVIDUAL  PROPHYLAXIS 
AGAINST  INFECTIOUS  DISEASES 


[Rerised  in  December,  1899,  by  the  Author.] 


GEORGE  M.  STERNBERG,  M.  D.,  L.L.  D. 

SurftoH-Gtntr*l  U.  S.  Army. 


AD    ASTRA    run.    ASI'RKA. 


ILUMBUS,  n)HO: 
i  in:  BERLIN   PRINTING  CO. 

1100. 


Copyright,  1886, 
By  Irving  A.  Watson,  Sec.  American  Public  Health  Association. 


Copyright,  1899, 
By  Charles  O.  Probst,  Sec.  American  Public  Health  Association. 


All  Rights  Reserved. 


I 

Note. — The  prize  essay  of  the  American  Public  Health  Association  on  Disin- 
fection and  Individual  Prophylaxis  against  Infectious  Diseases,  by  George  M. 
Sternberg,  Surgeon-Major,  U.  S.  Army,  met  with  a  large  sale  and,  perhaps 
more  than  any  other  treatise  on  the  subject,  served  as  a  guide  to  health  authori- 
ties in  the  use  of  disinfectants.  Since  its  publication  in  1886  immense  gains  have 
been  made  in  our  knowledge  of  disinfection  and  the  prevention  of  disease;  and 
it  is  with  pleasure  that  we  announce  that  the  distinguished  author  of  this  essay, 
now  Surgeon-General  of  the  United  States  Army,  has  just  revised  it  so  as  to 
include  the  essentials  of  what  has  been  found  of  value  in  the  practical  use  of 
disinfectants,  and  in  prophylaxis  against  disease. 

The  Publication  Committee  decided  to  print  the  revised  essay  in  Volume 
XXV.  of  the  transactions  of  the  Association,  but  copies  of  the  essay  alone  may 
be  secured  from  the  Essay  Department  of  the  Association,  Rochester,  N.  Y., 
H.  Lomb,  Supt. 

C.  O.  Probst,  Secretary. 


Loab  Prize  Essay. 


INTRODUCTION. 

As  the  result  of  prizes  offered  by  Mr.  Henry  Lomb,  of  Rochester, 
N.  Y.,  through  the  American  Public  Health  Association,  the  follow- 
ing awards  were  made  at  the  meeting  of  the  Association,  held  in  the 
city  of  Washington  in  1885. 

I.  Healthy  Homes  and  Foods  for  the  Working  Classes.  By 
Victor  C.  Vaughan,  M.  D.,  Ph.  D.,  Professor  in  University  of 
Michigan.      Prize    $200 

II.  The  Sanitary  Conditions  and  Necessities  of  School-Houses 
and  School-Life.  By  D.  F.  Lincoln,  M.  Dm  Boston,  Massa- 
chusetts.    Prize  $200 

III.  Disinfection    and    Individual    Prophylaxis    against    Infec- 

tious Diseases.  By  George  M.  Sternberg,  M.  D.,  Major  and 
Surgeon  U.  S.  Army.    Prize $500 

IV.  The  Preventable  Causes  of   Disease,   Injury  and    Death   in 

American  Manufactories  and  Workshops,  and  the  Best 
Means  and  Appliances  for  Preventing  and  Avoiding  them. 
By  George  H.  Ireland,  Springfield,  Massachusetts.     Prize $200 

That  these  essays  may  be  placed  in  the  hands  of  every  family  in  the 
country  is  the  earnest  desire  of  the  Association,  as  well  as  the  heartfelt 
wish  of  the  public-spirited  and  philanthropic  citizen  whose  unpreten- 
tious generosity  and  unselfish  devotion  to  the  interests  of  humanity 
have  given  us  these  essays,  but  the  financial  inability  of  the  Associa- 
tion renders  it  impossible  to  distribute  them  gratuitously ; — therefore 
a  price  covering  the  cost  has  been  placed  upon  these  publications.  It 
is  to  be  hoped,  however,  that  government  departments,  state  and  local 
boards  of  health,  sanitary  and  benevolent  associations,  etc.,  will  either 
publish  these  essays,  or  purchase  editions  at  cost  of  the  Association, 
for  distribution  among  the  people. 

Although  a  copyright  has  been  placed  upon  these  essays  for  legiti- 
mate protection,  permission  to  publish,  under  certain  conditions,  can 
be  obtained  by  addressing  the  secretary. 

i  Revised  in  December,  1899,  by  the  Author. 


DISINFECTION  AND  INDIVIDUAL  PROPHYLAXIS 
AGAINST  INFECTIOUS  DISEASES. 

By  GEORGE  M.  STERNBERG,  M.  D.,  L.L.  D.,  Surgeon-Genmal 

U.  S.  Army. 

[Revised  in  December,  1899,  by  the  Author.] 
INTRODUCTION. 

Definition.  We  are  met  at  the  outset  by  a  difficulty  growing  out  of 
the  fact  that  the  word  disinfection,  as  commonly  used,  has  a  very 
different  signification  from  that  to  which  certain  authors  would  re- 
strict it.  Thus,  the  Committee  on  Disinfectants  of  the  American 
Public  Health  Association  defines  a  disinfectant  as  "an  agent  capable 
of  destroying  the  infective  power  of  infectious  material."1  In  the 
preliminary  report  of  this  committee  the  reasons  for  restricting  the 
meaning  of  the  word  within  the  limits  justified  by  its  etymology,  and 
of  our  knowledge  of  the  nature  of  "infectious  material,"  are  very 
clearly  stated,  as  follows : 

"The  object  of  disinfection  is  to  prevent  the  extension  of  infectious 
diseases  by  destroying  the  specific  infectious  material  which  gives  rise 
to  them.     This  is  accomplished  by  the  use  of  disinfectants. 

"There  can  be  no  partial  disinfection  of  such  material :  either  its  in- 
fecting power  is  destroyed,  or  it  is  not.  In  the  latter  case  there  is  a 
failure  to  disinfect.  Nor  can  there  be  any  disinfection  in  the  absence 
of  infectious  material.     *       *       * 

"Popularly,  the  term  disinfection  is  used  in  a  much  broader  sense. 
Any  chemical  agent  which  destroys  or  masks  bad  odors,  or  which 
arrests  putrefactive  decomposition,  is  spoken  of  as  a  disinfectant. 
And  in  the  absence  of  any  infecti  his  disease  it  is  common  to  speak 
of  disinfecting  a  foul  cesspool,  or  a  bad-smelling  stable,  or  a  privy 
vault. 

"This  popular  use  of  the  term  has  led  t<>  much  misapprehension, 
and  the  agents  which  have  been  found  to  destroy  bad  odors — de- 
odorizers,— or  to  arrest  putrefactive  decomposition-antiseptics — 
have  been  confidently  recommended  and  extensively  used  for  the 
destruction  of  disease  germs  in  the  excreta  of  patient!  with  cholera, 
typhoid  fever,  etc. 

"The  injurious  consequences  which  are  likely  to  result  from  such 
misapprehension  and  misuse  of  the  word  disinfectant  will  be  appre- 

i   The  Mtditml  S'rwi,  Phlla..  Jan.  24,  1«*5,  y 
5 


6  DISINFECTION. 

ciated  when  it  is  known  that  recent  researches  have  demonstrated 
that  many  of  the  agents  which  have  been  found  useful  as  deodorizers, 
or  as  antiseptics,  are  entirely  without  value  for  the  destruction  of 
disease  germs. 

"This  is  true,  for  example,  as  regards  the  sulphate  of  iron  or  cop- 
peras, a  salt  which  has  been  extensively  used  with  the  idea  that  it  is 
a  valuable  disinfectant.  As  a  matter  of  fact,  sulphate  of  iron  in  sat- 
urated solution  does  not  destroy  the  vitality  of  disease  germs,  or  the 
infecting  power  of  material  containing  them.  This  salt  is,  neverthe- 
less, a  very  valuable  antiseptic,  and  its  low  price  makes  it  one  of  the 
most  available  agents  for  the  arrest  of  putrefactive  decomposition  in 
privy  vaults,  etc. 

"Antiseptic  agents  also  exercise  a  restraining  influence  upon  the 
development  of  these  germs,  and  their  use  during  epidemics  is  to  be 
recommended  when  masses  of  organic  material  in  the  vicinity  of 
human  habitations  cannot  be  completely  destroyed,  or  removed,  or 
disinfected. 

"While  an  antiseptic  agent  is  not  necessarily  a  disinfectant,  all  dis- 
infectants are  antiseptics ;  for  putrefactive  decomposition  is  due  to  the 
development  of  'germs'  of  the  same  class  as  that  to  which  disease 
germs  belong,  and  the  agents  which  destroy  the  latter  also  destroy 
the  bacteria  of  putrefaction,  when  brought  in  contact  with  them  in 
sufficient  quantity,  or  restrain  their  development  when  present  in 
smaller  amounts. 

"A  large  number  of  the  proprietary  'disinfectants'  so  called,  which 
are  in  the  market,  are  simply  deodorizers  or  antiseptics  of  greater  or 
less  value,  and  are  entirely  untrustworthy  for  disinfecting  purposes."1 

The  offensive  gases  given  off  from  decomposing  organic  material 
are  no  doubt  injurious  to  health ;  and  the  same  is  true,  even  to  a 
greater  extent,  of  the  more  complex  products  known  as  ptomaines, 
which  are  a  product  of  the  vital — physiological — processes  attending 
the  growth  of  the  bacteria  of  putrefaction  and  allied  organisms.  It 
is  therefore  desirable  that  these  products  should  be  destroyed;  and, 
as  a  matter  of  fact,  they  are  neutralized  by  some  of  the  agents  which 
we  recognize  as  disinfectants,  in  accordance  with  the  strict  definition 
of  the  term.  But  they  are  also  neutralized  by  other  agents — de- 
odorants— which  cannot  be  relied  upon  for  disinfecting  purposes,  and 
by  disinfectants,  properly  so  called,  in  amounts  inadequate  for  the 
accomplishment  of  disinfection.  Their  formation  may  also  be  pre- 
vented by  the  use  of  antiseptics.  From  our  point  of  view  the  destruc- 
tion of  sulphureted  hydrogen,  of  ammonia,  or  even  of  the  more 
poisonous  ptomaines,  in  a  privy  vault,  is  no  more  disinfection  than 

1  The  Medical  News,  Apr.  18, 1885,  p.  425. 


DISINFECTION.  7 

is  the  chemical  decomposition  of  the  same  substances  in  a  chemist's 
laboratory.  The  same  is  true  as  regards  all  of  the  bad-smelling  and 
little  known  products  of  decomposition.  None  of  these  are  "infec- 
tious material,"  in  the  sense  in  which  we  use  these  words ;  that  is,  they 
do  not,  so  far  as  we  know,  give  rise  directly  to  any  infectious  disease. 
Indirectly  they  are  concerned  in  the  extension  of  the  epidemic  "filth 
diseases,"  such  as  cholera,  yellow  fever  and  of  the  fatal  endemic  filth 
diseases,  such  as  typhoid  fever  and  diphtheria,  which  in  the  long  run 
claim  more  victims  than  do  the  pestilential  maladies,  first  named. 
This  because  persons  exposed  to  the  foul  emanations  from  sewers, 
privy  vaults,  and  other  receptacles  of  filth,  have  their  vital  resisting 
power  lowered  by  the  continued  respiration  of  an  atmosphere  con- 
taminated with  these  poisonous  gases,  and  are  liable  to  become  the 
victims  of  any  infectious  disease  to  which  they  may  be  exposed. 
Moreover,  the  accumulations  of  filth  which  give  off  these  offensive 
gases  furnish  pabulum  upon  which  certain  disease  germs  thrive ;  and 
it  may  happen  that  the  bad  smelling  air  carries  something  worse  than 
the  poisonous  gas  which  makes  its  presence  known  by  offending  the 
sense  of  smell.  It  may  waft  to  our  nostrils  infectious  particles  which 
are  beyond  recognition  by  any  sense,  unless  it  be  the  sense  of  sight 
with  the  aid  of  a  good  microscope. 

We  desire,  moreover,  to  have  it  fully  understood  that  in  restricting 
the  meaning  of  the  term  disinfection  within  the  limits  given  by  the 
definition  of  the  Committee  on  Disinfectants  of  the  American  Public 
Health  Association,  we  do  not  wish  to  limit  the  practice  of  "disinfec- 
tion," in  the  popular  sense  of  the  word. 

It  is  but  fair  to  say,  also,  that  this  popular  usage  is  supported  by 
good  authority,  and  until  quite  recently  has  been  the  common  ac- 
ceptation of  the  term  among  physicians  and  chemists.  Indeed,  it  is 
but  a  short  time  since  the  nose  test  was  the  only  test  of  "disinfection" 
recognized  by  many  intelligent  persons. 

Littre,  in  his  Dictionary  of  the  French  Language,  defines  disinfec- 
tants as  "substances  which  destroy,  chemically,  bad  od< 

Vallin,  the  author  of  a  valuable  treatise   upon   "Disinfection 
Disinfectants,"  says, — 

Om  a  scientific  point  of  view  there  is  perhaps  an  impropriety  in 
introducing   i n t < >   the    idea   of   disinfection    the    suppression    of    6d 
which  offend  the  sense  of  smell.     The  had  odor  is  not   injurious   in 
itself;  it  is  an  epiphenomenon,  which  does  not  I  the 

measure  of  the  hurtful  properties  of  the  air.  or  <>f  any  substance  what- 
ever.   The  public,  unacquainted  with  medicine,  baa  an  unfortuu 

tendency  to  judge  of  insalubrity  by  the  hail  0dOT|  the  ahsenre  of  this 
gives  to  it  a  deceitful  security:  when 


t  DISINFECTION. 

it  [the  public]  believes  that  all  danger  has  been  removed.  Neverthe- 
less it  is  necessary  to  avoid  violating  the  ordinary  sense  of  words.1  An 
atmosphere  which  does  not  in  the  least  offend  the  sense  of  smell  may 
certainly  be  insalubrious,  and  engender  the  gravest  maladies ;  but  the 
fetid  or  disagreeable  odors  may  reveal  the  presence  of  injurious  prin- 
ciples, of  toxic  gases,  or  of  organic  matter  in  decomposition.  We 
should  not  too  much  diminish  the  importance  of  these  offensive  odors 
in  the  eyes  of  the  public ;  everything  which  smells  badly  is  to  be  sus- 
pected."1 

We  agree  with  Prof.  Vallin,  that  the  bad  odors  should  arouse  suspi- 
cion, and  lead  to  the  use  of  deodorants,  or  of  antiseptics,  or  of  disin- 
fectants, if  required ;  but  let  us  not  leave  the  public  to  suppose  that 
when  the  bad  odors  have  been  neutralized,  the  offensive  material  has 
been  disinfected.  Let  us  rather  instruct  the  public  that  to  deodorize 
and  to  disinfect  are  not  synonymous  terms.  For  our  part  we  prefer 
to  "violate  the  ordinary  sense"  of  the  word,  and  to  restrict  its  signifi- 
cation within  such  limits  as  will  prevent  confusion,  and,  what  is  far 
worse,  a  reliance  upon  inefficient  methods  for  the  destruction  of  in- 
fectious material. 

In  the  present  essay  we  shall  use  the  words  disinfection  and  dis- 
infectant, in  accordance  with  the  definition  of  the  committee  on  disin- 
fectants already  given.  But,  inasmuch  as  this  is  intended  to  be  a 
practical  treatise  for  popular  use,  we  shall  also  give,  in  the  proper 
place,  directions  for  the  use  of  deodorants  and  of  antiseptics,  so  that 
"disinfection,"  in  the  broad  sense  in  which  the  word  is  commonly 
used,  may  be  fully  considered. 

Tests  of  Disinfection.  What  means  have  we  of  proving  that  the 
infective  power  of  infectious  material  has  been  destroyed? 

Evidence  of  disinfection  may  be  obtained  (a)  from  the  practical 
experiments — experience — of  those  engaged  in  sanitary  work;  (b)  by 
inoculation  experiments  upon  susceptible  animals ;  (c)  by  experi- 
ments made  directly  upon  known  disease  germs. 

(a)  It  is  a  matter  of  common  experience,  that  when  a  room  has 
been  occupied  by  a  patient  with  an  infectious  disease,  such  as  small- 
pox, scarlet  fever,  or  diphtheria,  susceptible  persons  are  liable  to 
contract  the  disease  weeks  or  even  months  after  the  patient  has  been 
removed  from  it,  unless  in  the  meantime  it  has  been  disinfected.  If 
a  second  case  does  occur  from  exposure  in  such  a  room,  it  is  evident 
that  it  has  not  been  disinfected.  But  the  non-occurrence  of  subse- 
quent cases  cannot  always  be  taken  as  evidence  that  the  means  of  dis- 
infection resorted  to  were  efficient.     Negative   evidence   should  be 

t  Italics  by  present  writer. 
*  Op.  Cit.,  p.  2. 


DISINFECTION.  9 

received  with  great  caution.  In  the  first  place,  the  question  as  to 
whether  susceptible  individuals  have  been  fairly  exposed  in  the  disin- 
fected room  must  be  considered.  Then  it  must  be  remembered  that 
susceptible  persons  do  not  always  contract  a  disease,  even  when  they 
are  exposed  in  a  locality  known  to  be  infected.  A  further  difficulty 
in  estimating  the  value  of  evidence  obtained  in  practice  arises  from 
the  fact,  that,  in  connection  with  the  special  means  of  disinfection 
resorted  to,  such  as  fumigation,  hanging  up  cloths  saturated  with  a 
disinfecting  solution,  etc.,  it  is  customary  to  resort  to  additional  pre- 
cautionary measures,  such  as  washing  surfaces  with  soap  and  hot 
water,  white-washing  plastered  walls,  and  free  ventilation.  It  is  ap- 
parent that  under  these  circumstances  it  would  be  unsafe  to  accept 
the  fact,  that  no  other  cases  occurred  in  a  room  treated  in  this  way, 
as  evidence  that  the  particular  disinfectant  used  is  efficient  for  the 
destruction  of  the  infectious  agent  of  the  disease  in  question.  The 
fond  mother  who  attaches  a  charm  to  her  child's  neck  to  protect  it 
from  evil,  also  takes  the  precaution  of  guarding  it  from  contact  with 
other  children  who  are  sick  with  any  infectious  disease.  If  her  child 
fortunately  grows  to  manhood  or  womanhood  without  having  suf- 
fered an  attack  of  scarlet  fever  or  diphtheria,  she  may  imagine  that 
her  charm  has  protected  it,  but  the  evidence  upon  which  her  faith  is 
founded  is  not  of  a  nature  to  convince  those  who  are  familiar  with 
scientific  methods  of  demonstration.  "Well  educated"  persons  are 
often  ready  to  testify  in  favor  of  methods  of  disinfection,  or  of  treat- 
ment, upon  evidence  which,  from  a  scientific  point  of  view,  has  no 
more  value  than  that  which  the  fond  mother  in  question  has  to  offer 
in  favor  of  the  little  bag  containing  camphor  or  assafcetida,  or  some 
other  charm  of  equal  value,  which  she  has  attached  to  her  child's  neck 
to  keep  it  from  catching  scarlet  fever  or  diphtheria  at  school.  On  a 
par  with  these  charms,  so  far  as  disinfection  is  concerned,  we  may 
place  the  saucer  of  chloride  of  lime,  which  it  was  formerly  the  fashion 
to  place  under  the  bed  of  a  patient  sick  with  an  infectious  disease,  the 
rag  saturated  with  carbolic  acid,  or  chloride  of  zinc,  suspended  in  the 
sick-room,  and  even  the  fumigations  with  burning  sulphur,  as  some- 
times practiced  by  those  who  arc  unfamiliar  with  the  evidence  as  to 
the  exact  value  of  this  agent,  and  the  conditions  necessary  to  ensure 
successful  disinfection  with  it. 

Chloride  of  lime,  sulphurous  acid  kras,  and  carbolic  acid  are  among 
our  most  useful  disinfecting  agents,  out  dis<  not  to  DC 

charmed  away  by  (hem  any  more  than  by  a  little  bag  of  camphor. 

Having  pointed  out  the  fact  that  negative  vx\<\vV,<v.  fa  ■  restricted 
field  of  observation,  must  br  accepted  witn  great  caution  in  estima- 
ting the  value  of  disinfectants,  we  hasten  I  that  the  combined 


10  DISINFECTION. 

experience  of  sanitarians,  derived  from  practical  efforts  to  restrict  the 
extension  of  infectious  diseases,  is  of  the  greatest  value,  and  that  this 
experience  is  to  a  great  extent  in  accord  with  the  results  of  exact 
experiments  made  in  the  laboratory. 

(b)  Inoculation  experiments  upon  susceptible  aniamls,  made  di- 
rectly with  infectious  material  which  has  been  subjected  to  the  action 
of  a  disinfectant,  have  been  made  by  numerous  observers.  The  proof 
of  disinfection  in  this  case  is  failure  to  produce  the  characteristic 
symptoms  which  result  from  inoculation  with  similar  material  not 
disinfected.  Thus,  Davaine  found  that  the  blood  of  an  animal  just 
dead  from  the  disease  known  by  English  writers  as  anthrax  or  splenic 
fever  (Fr.  Charbon),  inoculated  into  a  healthy  rabbit  or  guinea-pig, 
in  the  smallest  quantity,  infallibly  produces  death  within  two  or  three 
days ;  and  the  blood  of  these  animals  will  again  infect  and  cause  the 
death  of  others,  and  so  on  indefinitely.  This  anthrax  blood  therefore 
was  infectious  material,  which  could  be  utilized  for  experiments  re- 
lating to  the  comparative  value  of  disinfectants.  Davaine  made 
many  such  experiments,  not  only  with  the  blood  of  anthrax,  but  also 
with  that  of  a  fatal  form  of  septicaemia  in  rabbits,  which  is  known  by 
his  name.  Other  investigators  have  followed  up  these  experiments 
upon  infectious  material  of  the  same  kind,  and  also  upon  material 
from  other  sources — e.  g.,  the  infectious  material  of  glanders,  of  tuber- 
culosis, of  symptomatic  anthrax,  of  fowl  cholera,  of  swine  plague,  etc. 

It  has  been  proved  that  the  infectious  agent  in  all  of  the  diseases 
mentioned  is  a  living  germ,"  and  that  disinfection  consists  in  destroy- 
ing the  vitality  of  this  germ.  But  in  experiments  made  with  blood  or 
other  material  obtained  directly  from  diseased  animals,  the  results 
would  be  just  as  definite  and  satisfactory  if  we  were  still  ignorant  as 
to  the  exact  nature  of  the  infecting  agent.  The  test  shows  the  de- 
struction of  infecting  power  without  any  reference  to  the  cause  of  the 
special  virulence,  which  is  demonstrated  to  be  neutralized  by  certain 
chemical  agents  in  a  given  amount.  All  of  the  experiments  made 
with  the  above  mentioned  kinds  of  virus  have  been  made  upon  the 
lower  animals ;  but  there  is  one  kind  of  material  which  it  is  justifiable 
to  use  upon  man  hims  If,  and  with  which  numerous  experiments  of  a 
very  satisfactory  character  have  been  made.  This  material  is  vaccine 
virus.  Fresh  vaccine,  when  inoculated  into  the  arm  of  an  unvacci- 
nated  person,  gives  rise  to  a  very  characteristic  result, — the  vaccine 
vesicle.  The  inference  seems  justified  that  any  agent  which  will 
neutralize  the  specific  infecting  power  of  this  material  will  also  neu- 
tralize the  smallpox  virus.  Thus  far  it  has  not  been  definitely 
proved  that  the  infective  agent  in  vaccine  virus  is  a  living  germ ;  but 
the   numerous   experiments    made    have   shown   that   the   chemical 


DISINFECTION.  11 

agents,  which  have  the  power  of  destroying  the  various  kinds  of  in- 
fectious material  heretofore  mentioned,  have  also  the  power,  in  about 
the  same  amounts,  of  neutralizing  vaccine  virus,  as  shown  by  its  fail- 
ure to  produce  any  result  when  inoculated  into  an  unvaccinated  per- 
son. In  these  experiments  the  more  careful  investigators  have  taken 
the  precaution  of  vaccinating  the  same  person  with  disinfected  and 
non-disinfected  virus  from  the  same  source.  A  successful  vaccina- 
tion with  the  non-disinfected  virus  shows  that  the  individual  is  sus- 
ceptible, and  the  material  good :  failure  to  produce  any  result  is  evi- 
dence that  the  potency  of  the  disinfecte  1  virus  has  been  destroyed  by 
the  chemical  agent  to  which  it  was  exposed. 

(V)  As  already  stated,  it  has  been  demonstrated  that  the  infectious 
diseases  of  the  lower  animals,  which  have  furnished  the  material  for 
experiments  upon  disinfectants  by  the  method  of  inoculation,  are 
''germ  diseases,"  and  that  the  infectious  agent  is  in  each  case  a  living 
microorganism,  belonging  to  the  class  known  under  the  general  name 
of  Bacteria.  The  bacteria  are  vegetable  organisms,  which,  by  reason 
of  their  minute  size  and  simple  organization,  must  be  placed  at  the 
very  foot  of  the  scale  of  living  things.  But  they  make  up  in  number 
and  in  rapidity  of  development  for  their  minute  size ;  and  there  is 
good  reason  for  believing  that  the  infectious  diseases  of  man  are  also 
caused  by  pathogenic — disease-producing — organisms  of  the  same 
class.  Indeed,  this  has  already  been  proved  for  some  of  these  dis- 
eases, and  the  evidence  as  regards  several  others  is  so  convincing  as 
to  leave  very  little  room  for  doubt. 

Many  of  these  disease  germs  are  now  known  to  us,  not  only  by 
microscopic  examination  of  the  blood  and  tissues  of  infected  animals, 
but  also  by  "culture  experiments."  That  is,  we  are  able  to  cultivate 
them  artificially  in  suitable  media,  and  to  study  their  mode  of  devel- 
opment, etc.,  in  the  laboratory,  quite  independently  of  the  animals 
from  which  our  "pure  cultures"  were  obtained  in  the  first  instance. 
The  culture  fluids  used  are  prepared  from  the  flesh  of  various  ani- 
mals; and  when  to  one  of  these  a  certain  quantity  of  gelatine  is  added. 
we  have  a  "solid  culture  medium,"  upon  the  surface  of  which  some  of 
these  germs  will  grow  most  luxuriantly.  To  start  such  a  "cultUl 
only    n<  fer,   with    proper   precautions,    a    mint 

quantity  <>f  the  infectious  material  to  the  surl  ur  cultui 

dium,  or  into  a  fluid  which    has  been  found  to  be   suit 
growth  of  the  particular  organism  which  titivate.      \ 

nil  culture  is  in  the  d  from  the  first,  and    io  f,n 

indefinitely. 

Now  it   is   evident    that    these   "pure   cultures"   furnish    I 
means  for  testiii<r  the  power  ,it   various  chemical 


12  DISINFECTION. 

the  vitality  of  known  disease  germs,  as  shown  by  their  failure  to  grow 
in  a  suitable  culture  medium  after  exposure  for  a  given  time  to  a 
given  percentage  of  the  disinfectant.  Very  many  experiments  of  this 
nature  have  been  made.  The  reader  who  desires  fuller  details  as  to 
the  method  of  conducting  such  experiments,  and  of  the  results  ob- 
tained, is  referred  to  the  preliminary  reports  of  the  committee  on 
disinfectants,  of  the  American  Public  Health  Association,  published 
in  1885  in  the  Medical  News,  Philadelphia,  and  also  published  in  full 
in  the  annual  volume  of  the  Association  for  1888.  We  may  say  here, 
that  the  experimental  ata  on  record  indicate  that  those  agents  which 
are  efficient  for  the  destruction  of  any  one  of  the  pathogenic  organ- 
isms upon  which  experiments  have  been  made,  or  of  harmless  species 
of  the  same  class, — e.  g.,  the  bacteria  of  putrefaction, — are  efficient 
for  the  destruction  of  all,  in  the  absence  of  spores.  There  is,  it  is  true, 
within  certain  limits,  a  difference  in  the  resisting  power  of  different 
organisms  of  this  class  to  chemical  agents.  This  is  not,  however, 
sufficiently  marked  to  prevent  the  general  statement  that  a  disin- 
fectant for  one  is  a  disinfectant  for  all,  in  the  absence  of  spores. 

The  last  clause  of  the  above  statement  calls  for  an  explanation,  and 
certain  details  with  reference  to  the  mode  of  reproduction  of  disease 
germs.  All  of  the  bacteria  multiply  by  binary  division;  that  is,  one 
individual  divides  into  two,  and  each  member  of  the  pair  again  into 
two,  and  so"  on.  The  spherical  bacteria,  known  as  micrococci,  multiply 
only  in  this  way,  but  the  rod-shaped  bacteria,  or  bacilli,  also  form 
spores.  These  spores  correspond  with  the  seeds  of  higher  plants. 
They  are  highly  refractive,  oval  or  spherical  bodies,  which,  under 
certain  circumstances,  make  their  appearance  in  the  interior  of  the 
rods,  which  cease  to  multiply  by  binary  division  when  spore  forma- 
tion has  taken  place.  The  point  of  special  interest  with  reference  to 
these  spores  is,  that  they  have  a  resisting  power  to  heat,  and  to  the 
action  of  chemical  disinfectants,  far  beyond  that  which  is  possessed 
by  micrococci,  or  by  bacilli  without  spores.  The  difference  may  be 
compared  to  the  difference  between  a  tender  plant  and  its  seeds  to 
deleterious  influences,  such  as  extremes  of  heat  and  cold.  Thus  the 
spores  of  certain  species  of  bacilli  withstand  a  boiling  temperature 
for  several  hours,  while  a  temperature  of  150°  Fahr.  quickly  kills 
most  bacteria  in  the  absence  of  spores.  A  similar  difference  is  shown 
as  regards  the  action  of  chemical  agents.  Certain  agents, — e.  g., 
sulphurous  acid  gas  and  carbolic  acid, — which  are  extensively  used 
as  disinfectants,  have  been  proved  by  exact  experiments  to  be  quite 
impotent  for  the  destruction  of  spores.  This  being  the  case,  it  is 
advisable,  in  practical  disinfection,  always  to  use  an  agent  which  has 
the  power  of  destroying  spores,  in  those  cases  in  which  the  exact 


DISINFECTION.  13 

nature  of  the  disease  germ  has  not  been  demonstrated.  The  cholera 
germ  of  Koch  does  not  form  spores ;  and  there  is  good  reason  to  be- 
lieve that  the  same  is  true  as  regards  the  germs  of  yellow  fever,  of 
scarlet  fever,  and  of  small-pox,  which  have  not  yet  been  demon- 
strated. This  inference  is  based  upon  evidence  obtained  in  the  prac- 
tical use  of  disinfectants,  and  upon  certain  facts  relating  to  the  propa- 
gation of  these  diseases. 

A  second  general  statement,  which  is  justified  by  the  experimental 
evidence  on  record,  is,  that  agents  which  kill  bacteria  in  a  certain 
amount,  prevent  their  multiplication  in  culture  fluids,  when  present  in 
quantities  considerably  less  than  are  required  to  completely  destroy  vitality. 
An  agent,  therefore,  which,  in  a  certain  proportion  and  in  a  given 
time,  acts  as  a  "germicide"  in  a  smaller  quantity,  may  act  as  an  anti- 
septic, i.  c.,  may  prevent  putrefactive  decomposition  by  restraining 
the  development  of  the  bacteria  of  putrefaction.  Antiseptics  also 
prevent  or  retard  the  development  of  pathogenic  bacteria.  It  follows 
from  this  that  germicides  are  also  antiseptics ;  but  the  reverse  of  this 
proposition  is  not  true  as  a  general  statement,  for  all  antiseptics  are 
not  germicides.  Thus  alcohol,  common  salt,  sulphate  of  iron,  and 
many  other  substances  which  are  extensively  used  as  antiseptics,  have 
scarcely  any  germicide  power,  even  in  concentrated  solutions,  and 
consequently  would  be  entirely  unreliable  as  disinfectants. 

Practically,  antiseptics  may  accomplish  the  same  result  in  the  long 
run  as  we  obtain  in  a  short  time  by  the  use  of  disinfectants.  If,  for 
example,  we  prevent  the  development  of  the  germs  of  cholera,  or  of 
typhoid  fever,  in  an  infected  privy  vault,  by  the  continued  use  of  anti- 
septics, these  germs  will  in  time  lose  tl  eir  ability  to  grow,  when  in- 
troduced in  to  a  suitable  culture  medium.  But  in  the  meantime 
there  is  always  the  possibility  that  some  of  them  may  escape,  with  the 
fluid  contents  of  the  vault,  into  the  surrounding  soil,  and  contaminate 
some  well  or  stream  from  which  drinking-water  is  obtained.  1 
this  reason  privy  vaults,  cesspools,  and  sewers  should  never  be  allow- 
ed to  become  infected.  All  infectious  material,  BUch  as  the  dejections 
of  patients  with  cholera  or  typhoid  fever,  should  be  i  1  at  its 

source,  in  the  sick-room;  or,  if  it  is  ascertained  that  such  material 
has  been  thrown  into  a  privy  vault,  the  entire  contents  of  the  vault 
should  be  promptly  disinfected.  The  same  rule  applies  to  infectious 
material  thrown  upon  the  ground,  or  wherever  it  may  be. 
Finally,  we  desire  to  emphasize  the  following  propositions: 
Disinfection  consists  in  extinguishing  the  spark,  killing  the  germ. 
which  may  light  up  an  epidemic  in  the  presence  of  a  supply  of  com- 
bustible material — filth. 


14  DISINFECTION. 

The  object  of  general  sanitary  police  is  to  remove  this  combustible 
material  out  of  the  way.  so  that  no  harm  may  result  even  if  the  spark 
be  introduced. 

Antiseptics  and  deodorants  are  useful  when  it  is  impracticable  to  re- 
move offensive  organic  material  from  the  vicinity  of  human  habita- 
tions, but  they  are  a  poor  substitute  for  cleanliness. 

PART  FIRST. 

DISINFECTION. 

It  will  be  our  aim  in  the  present  chapter  to  give  reliable,  practical 
directions  with  reference  to  the  use  of  disinfectants,  und  the  best 
methods  of  disinfection.  Keeping  this  object  in  view,  we  shall  rec- 
ommend for  disinfecting  purposes  only  those  agents  named  in  the 
following  list: 

1.  Fire. 

2.  Steam  under  pressure  (20  pounds). 

3.  Boiling  water. 

4.  Formaldehyd  gas. 

5.  Chloride  of  lime  (in  solution). 

6.  Mercuric  chlorid  (in  solution). 

7.  Carbolic  acid  (5  per  cent,  solution). 

8.  Caustic  lime  ("quicklime"). 

9.  Dry  heat  (230°  Fahr.  for  two  hours). 

10.  Sulphur  dioxid. 

11.  Copper  sulphate  (in  solution). 

12.  Zinc  chlorid  (in  solution). 

All  of  these  agents,  properly  used,  are  effective  for  the  destruction 
of  the  "germs"  of  the  following  named  diseases :  Tuberculosis, 
diphtheria,  typhoid  fever,  yellow  fever,  cholera,  small-pox,  measles, 
pneumoina,  epidemic  influenza,  erysipelas,  hog  cholera,  chicken 
cholera,  swine  plague,  infectious  pleuro-pneumonia  of  cattle  and,  in 
general,  of  all  infectious  diseases  in  which  the  specific  germ  does  not 
form  spores.  The  five  agents  at  the  head  of  the  list  may  also  be  re- 
lied upon  for  the  destruction  of  the  spores  of  anthrax,  tetanus  and 
symptomatic  anthrax,  which  are  the  principal  diseases  in  which  it 
has  been  demonstrated  that  resistant  spores  are  present  in  the  infec- 
tious material  by  which  they  are  propagated. 

We  shall  first  give  a  brief  account  of  the  conditions  of  successful 
disinfection  with  these  agents,  as  established  by  experimental  data, 
and  afterward  detailed  directions  for  their  employment  under  the 
various  circumstances  in  which  disinfection  is  required. 


DISINFEC'1I0.\.  IS 

1.  Fire.  It  is  hardly  necessary  to  say  that  burning  of  infectious 
material,  infected  clothing,  etc.,  is  an  effectual  method  of  disposing 
of  it.  This  method  of  disinfection  is  always  to  be  recommended, 
when  practicable  or  consistent  with  a  due  regard  for  economy  and 
the  rights  of  individuals.  As  a  rule,  articles  of  little  value,  which 
have  been  soiled  with  infectious  material,  had  better  be  burned ;  and 
this  is  especially  true  of  old  clothing  and  bedding.  But  we  have 
other  efficient  methods  of  disinfection,  which  make  it  unnecessary  to 
sacrifice  articles  of  value  except  under  unusual  circumstances. 

2.  Steam  under  Pressure.  The  disinfecting  power  of  steam  given 
off  from  boiling  water  in  an  open  vessel  does  not  differ  from  that  of 
the  water  itself,  but  confined  steam  has  a  temperature  corresponding 
with  the  pressure  as  indicated  by  a  steam  ga  ge.  At  twenty  pounds 
pressure  the  temperature  is  about  230°  Fahr.  (105°  C.) ;  at  twenty- 
five  pounds  it  is  about  240°  Fahr. ;  at  thirty  pounds  it  is  250°  Fahr. 
Moist  heat  at  the  lowest  temperature  named  destroys  the  most  re- 
sistant spores  in  twenty  minutes,  while  a  temperature  of  240°  Fahr. 
is  effective  almost  immediately 

3.  Boiling.  In  the  absence  of  spores,  bacteria  are  quickly  killed  at 
a  temperature  considerably  below  the  boiling  point  of  water,  and  it  is 
safe  to  say  that  boiling  for  half  an  hour  will  destroy  all  known  disease 
germs,  including  the  spores  of  anthrax,  which  have  less  resisting 
power  than  the  spores  of  certain  harmless  and  widely  distributed 
bacilli,  which  have  been  found  to  resist  boiling  for  severa1  hours. 

As  a  matter  of  fact  a  temperature  considerably  below  the  boiling- 
point  of  water  (140-160°  Fahr.),  destroys  within  a  few  minutes  the 
germs  of  cholera,  typhoid  fever,  diphtheria,  pneumonia,  erysipelas 
and  many  other  known  disease  germs. 

4.  Formaldehyd  Gas.  Since  the  first  edition  of  this  "prize  essay"  was 
published  (in  L886)  the  most  valuable  addition  to  our  knowledge  of 
disinfecting  agents  has  been  the  discovery  of  the  germicidal  action  of 
formaldehyd,  and  this  gas  is  now  la:  d  for  the  disinfection  of 
clothing.  I  wards,  etc.,  as  a  substitute  for  steam  or  for  sulphur 
dioxid.  But  like  these  agents  its  action  is  superficial  and  it  cannot  he 
depended  upon  for  the  disinfection  of  matt  f  cloth- 
ing or  bedding,  etc.  with  chlorine  and  sulphur  dioxid 
its  germicidal  power  is  increased  by  the  1  "f  moisture,  and  by 
a  high  temperature.  By  1  cans  of  a  vacuum  chamber,  in  which  the 
articles  to  he  disinfected  can  he  placed  and  the  air  exhausted  prior  to 
the  admission  of  the  di  l,  the  n<  penetration  can  be 
secured  for  ^uch  articles,  when  they  are  properly  arranged.  But  •' 
infection  of  clothing  ami  bedding  by  tl  m,  sulphur 
dioxid  and    formaldehyd),   calls   for   special   apparatus   and   the   su; 


16  DISINFECTION. 

vision  of  an  expert  in  the  practical  use  of  such  apparatus.  Formalde- 
hyd  gas  is  irritating  to  the  mucous  membrane  of  the  eyes  and  nose, 
but  it  is  not  poisonous.  It  is  produced  either  by  the  application  of 
heat  to  an  aqueous  solution  of  the  gas  (formalin),  or  by  the  oxidation 
of  wood  alcohol,  or  by  the  volatization  (by  heat)  of  paraform.  Various 
forms  of  apparatus  have  been  devised  for  generating  the  gas.  In  the 
army  the  large  "Formal  Gas  Generator"  (No.  2)  of  the  Kny-Scherrer 
Co.,  and  the  smaller  apparatus  manufactured  by  Chas.  Lentz  &  Sons 
of  Philadelphia,  have  been  used  with  success. 

5.  Chloride  of  Lime  (chlorinated  lime,  bleaching  powder).  This  is 
one  of  the  cheapest  and  most  efficient  of  disinfectants.  It  should  be 
packed  in  air-tight  and  moisture-proof  receptacles, — glass  is  prefer- 
able,— and  should  contain  at  least  25  per  cent,  of  available  chlorine. 
It  should  be  used  in  solution,  which  had  better  be  made  as  required. 
An  insoluble  residue  will  be  left,  which  may  be  removed  by  filtration 
or  decantation.  This,  however,  is  not  at  all  necessary.  Chlorinated 
lime  owes  its  disinfecting  power  to  the  presence  of  the  hypo-chlorite  of 
lime,  a  salt  which  is  freely  soluble  in  water,  and  which  is  quickly  de- 
composed by  contact  with  organic  matter.  Germs  of  all  kinds,  in- 
cluding the  most  resistant  spores,  are  destroyed  by  this  solution,  but  it 
must  be  remembered  that  the  disinfectant  itself  is  quickly  decomposed 
and  destroyed  by  contact  with  organic  matter,  and  that  if  this  is  pres- 
ent in  excess;  disinfection  may  not  be  accomplished,  especially  when 
the  germs  are  embedded  in  masses  of  material  which  are  left  after  the 
hypo-chlorite  oi  lime  has  all  been  exhausted  in  the  solution. 

6.  Mercuric  Chloride  (bichloride  of  mercury,  corrosive  sublimate). 
This  salt  is  well  known  as  a  deadly  poison,  which  has  long  been  used 
in  domestic  practice  as  a  "bug  poison."  It  has  germicide  powers  of 
the  first  order,  and  it  is  consequently  a  disinfectant  which  may  be  rec- 
ommended for  certain  purposes,  due  regard  being  had  to  its  poisonous 
nature,  and  to  the  fact  that  it  is  decomposed  by  contact  with  lead,  tin, 
or  copper,  and  that  lead  pipes  are  soon  rendered  brittle  and  worthless 
by  passing  through  them  solutions  of  mercuric  chloride.  Its  potency 
in  dilute  solutions  (1  :  500  to  1  :  4000)  makes  it  comparatively  cheap,1 
and  the  danger  of  accidental  poisoning  from  such  dilute  solutions  is 
not  very  great.  The  concentrated  solutions  should  be  colored,  as  a 
precaution  against  accident,  for  they  have  neither  color  nor  odor  to 
reveal  their  deadly  nature. 

A  standard  solution  which  contains  four  ounces  to  the  gallon  of 
water  is  of  convenient  strength  for  a  concentrated  solution,  to  be  issued 
by  manufacturers  or  health  authorities,  in  properly  labelled  bottles. 

1  It  cost  about.  SO  cents  a  pound  by  the  quantity. 


DISINFECTION.  17 

This  may  be  colored  with  permanganate  of  potash,1  or  with  indrgo,  or 
with  aniline  blue. 

It  must  be  remembered,  in  using  this  and  other  disinfecting  solu- 
tions, that  the  condition  relating  to  time  of  exposure  to  the  action  of 
the  disinfecting  agent  is  an  important  one.  The  experimental  evi- 
dence relating  to  the  germicide  power  of  mercuric  chloride  shows  that 
the  time  of  exposure  being  two  hours,  this  salt  may  be  safely  recom- 
mended for  the  destruction  of  pathogenic  organisms  in  the  absence  of 
spores  in  the  proportion  of  1  :  2000,  or  even  less,  provided  that  the 
micro-organisms  to  be  destroyed  are  fairly  exposed  to  its  action.  The  fact 
that  mercuric  chloride  combines  with  and  coagulates  albuminous  ma- 
terial, interferes  to  some  extent  with  its  value  as  a  disinfectant,  and  will 
be  kept  in  view  in  the  recommendations  to  be  made  hereafter  relating 
to  the  practical  use  of  this  agent.  Mercuric  chloride  is  an  efficient  an- 
tiseptic in  the  proportion  of  1  :  15,000,  and  it  exercises  a  restraining 
influence  upon  the  development  of  the  spores  of  the  anthrax  bacillus, 
when  present  in  culture  solutions,  in  the  proportion  of  1  :  300,000,  and 
even  less. 

7.  Carbolic  Acid.  The  disinfecting  power  of  carbolic  acid  has  been 
fixed  by  experiments  upon  vaccine  virus,  and  upon  various  pathogenic 
organisms.  A  saturated  aqueous  solution  cannot,  however,  be  relied 
upon  for  the  destruction  of  spores ;  but  in  the  absence  of  spores  it  is 
fatal  to  micro-organisms  in  the  proportion  of  two  per  cent.,  the  time 
of  exposure  being  two  hours.  Indeed,  less  than  one  per  cent,  is  fatal 
to  several  of  the  species  of  pathogenic  micrococci  which  have  served 
as  test-organisms  in  the  numerous  experiments  which  have  been  made 
with  this  agent.  Upon  the  recommendation  of  the  famous  Dr.  Koch, 
the  discoverer  of  the  cholera  spirillum,  the  committee  on  disinfectants, 
of  the  International  Sanitary  Conference  of  Rome  (1885),  has  given 
this  agent  the  first  plafce  for  disinfecting  soiled  clothin  *a,  etc., 

in  cholera.     For  excreta  it  is  to  be  used  m  five  per  cent,  solution,  and 
for  clothing,  etc.,  in  two  per  cent,  solution.     I  he  experimental  e 
dence  upon  record  indicates  that  it  may  be  relied  upon  in  this  propor- 
tion. 

S.  Caustic  Lime  ("Quicklime").  All  of  the  caustic  alkalies  hav< 
cided  germicidal  value,  but  quicklime  is  the  cheapest  and  most  gener- 
ally useful.  For  the  disinfection  of  excreta,  in  the  sick  room  or  in 
sinks,  privy-vaults,  etc.,  freshly  prepared  "milk  of  lime"  should  be 
■  !,  containing  about  one  part,  by  weight,  of  hydrate  of  lime  to  eight 
parts  of  water.  This  should  be  used  freely,  in  quantity  equal  in 
amount  to  the  material  t<>  be  disinfected.     The  white-washing 

«  Tni  k'r. mis  to  the  ralloa 


18  DISINFECTION. 

posed  surfaces  is  a  satisfactory  method  of  destroying  any  disease  germs 
which  may  have  lodged  upon  such  surfaces. 

g.  Dry  Heat.  Dry  heat  is  only  to  be  recommended  for  the  disinfec- 
tion of  such  articles  as  would  be  injured  by  exposure  to  moist  heat,  or 
to  a  disinfecting  solution.  A  properly  constructed  disinfection  cham- 
ber or  "oven"  is  absolutely  essential,  if  dry  heat  is  to  be  used.  The 
experimental  evidence  on  record  shows  that  the  destruction  of  spores 
requires  a  temperature  which  would  injure  woolen  fabrics  (140°  C.  for 
three  hours).  In  the  absence  of  spores,  however,  articles  which  are 
freely  exposed  for  two  hours  to  a  temperature  of  110°  C.  (230°  Fahr.) 
may  with  safety  be  considered  disinfected.  In  practice  it  will  be  neces- 
sary to  remember  that  the  penetrating  power  of  dry  heat  is  very  slight, 
and  that  packages,  bundles,  or  even  articles  loosely  thrown  one  upon 
another,  cannot  be  disinfected  in  this  way. 

io.  Sulphur  Dioxid  (sulphurous  acid  gas).  Fumigation  with  burn- 
ing sulphur  has  long  been  a  favorite  method  of  disinfection.  The  ex- 
perience of  sanitarians  is  in  favor  of  its  use  in  yellow  fever,  smallpox, 
scarlet  fever,  diphtheria,  and  other  diseases  in  which  there  is  reason  to 
believe  that  the  infectious  material  does  not  contain  spores.  The  ex- 
perimental evidence  on  record  shows  that  under  certain  conditions  it 
is  effective  for  the  destruction  of  micro-organisms  in  the  absence  of 
spores,  but  that  it  is  quite  impotent  for  the  destruction  of  these  repro- 
ductice  elements. 

The  presence  of  moisture  adds  greatly  to  the  disinfecting  power  of 
this  agent.  It  is  freely  soluble  in  water,  one  volume  dissolving  fifty 
volumes  of  the  gas.  It  is  therefore  evident  that  a  saturated  aqueous 
solution  is  fifty  times  as  strong  as  the  pure  gas — anhydrous.  In 
aqueous  solution,  in  the  proportion  of  1  :  2000  by  weight,  sulphur  di- 
oxide kills  micrococci  in  two  hours'  time.  In  gas-tight  receptacle  it 
destroys  the  infecting  power  of  vaccine  virus  dried  upon  ivory  points, 
when  present  in  the  proportion  of  one  volume  per  cent.,  the  time  of  ex- 
posure being  six  hours.  The  same  proportion  destroys  anthrax 
bacilli,  without  spores,  from  the  spleen  of  an  animal  recently  dead,  dried 
upon  silk  threads,  in  thirty  minutes  (Koch).  These  facts  show  that 
sulphur  dioxid  is  a  valuable  disinfectant;  but  the  conditions  of  suc- 
cessful disinfection,  as  established  by  the  experimental  evidence,  are, 
that  the  material  to  be  disinfected  shall  be  freely  exposed  to  its  action 
for  a  considerable  time,  in  a  receptacle  which  does  not  permit  the  gas  to 
escape.  It  must  be  remembered  that  disinfection  of  a  thin  layer  of  vac- 
cine virus  upon  an  ivory  point,  or  of  anthrax  blood  upon  a  silk  thread, 
exposed  in  a  gas-tight  receptacle,  cannot  be  taken  as  evidence  that 
thicker  layers  of  infectious  material,  attached  to  the  surface  of  bedding 
and  clothing,  or  enclosed  in  folded  blankets,  bundles  of  clothing,  mat- 


DISINFECTION.  19 

tresses,  *etc,  can  be  disinfected  by  the  same  amount  of  sulphur  dioxid 
generated  in  a  room  which  is  not  gas-tight.  It  has  been  shown,  by 
carefully  conducted  experiments,  that  the  escape  of  sulphurous  acid 
gas  from  a  bed-chamb  r  or  hospital  ward  is  very  rapid,  in  spite  of  the 
usual  precautions  for  stopping  up  crevices  when  such  a  room  is  to  be 
fumigated;  and  infectious  material,  enclosed  in  bundles  or  protected  by 
folds  of  blankets,  etc.,  may  escape  disinfection,  after  having  been  ex- 
posed for  many  hours  in  a  tightly  closed  chamber  containing  ten  vol- 
umes per  cent,  of  this  gas. 

ii.  Copper  Sulphate.  This  salt  has  been  largely  used  as  a  disinfect- 
ant in  France,  and  experiments  show  that  in  the  proportion  of  one  per 
cent,  it  is  a  reliable  agent  for  the  destruction  of  micro-organisms,  in 
the  absence  of  spores.  It  is  much  below  mercuric  chloride  in  germi- 
cide power,  but  is  a  better  deodorant — not  a  better  antiseptic — than  the 
more  poisonous  salt.  When  we  take  into  account  its  efficiency,  it  is 
comparatively  cheap,  and  is  to  be  recommended  for  certain  purposes. 

12.  Zinc  Chlorid.  Solutions  of  chloride  of  zinc  are  largely  used  in 
this  country  and  in  Europe  for  disinfecting  purposes.  It  is  an  excellent 
antiseptic  and  .deodorant,  but  its  power  to  destroy  disease  germs  has 
been  very  much  overestimated.  It  may,  however,  be  relied  upon  for 
the  destruction  of  pathogenic  organisms,  in  the  absence  of  spores,  in 
solutions  which  contain  from  five  to  ten  per  cent,  of  the  salt. 

GENERAL  DIRECTIONS  FOR   DISINFECTION. 

In  the  sick-room  we  have  disease  germs  at  an  advantage,  for  we 
know  where  to  find  them,  as  well  as  how  to  kill  them.  Having  this 
knowledge,  not  to  apply  it  would  be  criminal  negligence,  for  our  efforts 
to  restrict  the  extension  of  infectious  diseases  must  depend  largely 
upon  the  proper  use  of  disinfectants  in  the  sick-room. 

Disinfection  of  Excreta,  etc.  The  dejections  of  patients  suffering 
from  an  infectious  disease  should  be  disinfected  before  they  are  thrown 
into  a  water-closel  or  privy  vault.  This  is  especially  important  in 
cholera,  typhoid  fever,  yellow  fever,  and  other  diseases  in  which  there 
is  evidence  that  the  infectious  agent  is  capable  of  self-multiplication,  in 
suitable  pabulum,  external  to  the  human  body.  Vomited  matters,  and 
the  sputa  of  patients,  with  these  and  other  infectious  .  should 

•  lie  promptly  disinfected.     This  i>  especially  important  in  cholera, 
diphtheria,  scarlet  fever,  whooping-cough,  and  tuberculosis.      It  is  ad- 
visable, also,  to  treat  the  urine  of  patients  sick  with  an  infectn 
with  a  disinfecting  s<  >luti<  in. 

for  the  disinfection  of  excreta,  etc..  in   the   sick-room,  a   solution   of 

ride  of  lime  is  to  he    recommended.     This    is  an  excellent  ami 
prompt  deodorant,  as  well  as  a  disinfectant     A  quart  of  the  standard 


20  DISINFECTION. 

solution  (No.  1),  recommended  by  the  committee  on  disinfectants,  of 
the  American  Public  Health  Association,  will  suffice  for  an  ordinary 
liquid  discharge  in  cholera  or  typhoid  fever ;  but  for  a  copious  discharge 
it  will  be  prudent  to  use  twice  this  quantity,  and  for  solid  fecal  matter  a 
stronger  solution  will  be  required.  As  chloride  of  lime  is  quite  cheap, 
it  will  be  best  to  keep  on  the  safe  side,  and  to  make  the  solution  for  the 
disinfection  of  excreta  by  dissolving  eight  ounces  of  chloride  of  lime  in 
a  gallon  of  water.  This  solution  should  be  placed  in  the  vessel  before 
it  receives  the  discharge.  The  material  to  be  disinfected  should  be 
well  mixed  with  the  disinfecting  solution  by  agitating  the  vessel,  and 
from  thirty  minutes  to  an  hour  should  be  allowed  for  the  action  of  the 
disinfectant,  before  the  contents  are  thrown  into  a  water-closet  or  privy 
vault. 

For  the  disinfection  of  liquid  discharges  in  cholera,  typhoid  fever, 
dysentery,  etc.,  a  five  per  cent',  solution  of  carbolic  acid  may  be  used. 
This  was  recommended  by  the  committee  on  disinfectants  of  the  Inter- 
national Sanitary  Conference,  which  met  in  the  city  of  Rome  in  1885, 
of  which  committee  the  distinguished  bacteriologist,  Prof.  Robert 
Koch,  was  chairman  and  the  present  writer  a  member.  The  solution 
should  be  used  in  an  amount  at  least  equal  to  the  material  to  be  disin- 
fected— better  twice  this  amount.  The  time  necessary  to  insure  dis- 
infection was  fixed  by  the  committee  at  four  hours. 

Milk  of  lime,  made  by  slaking  fresh  quicklime  with  water  and  mixing 
the  resulting  hydrate  of  lime  with  eight  parts  of  water,  is  one  of  the  best 
and  cheapest  agents  for  the  disinfection  of  excreta  in  the  sick-room,  on 
the  surface  of  the  ground,  in  open  sinks,  etc.  This  milk  of  lime  should 
be  used  in  an  amount  at  least  equal  to  the  quantity  of  material  requiring 
disinfection. 

Chloride  of  zinc  in  ten  per  cent,  solution  may  be  used  to  disinfect 
the  dejections  of  those  sick  with  cholera  or  typhoid  fever,  or  sulphate 
of  copper  in  a  solution  of  the  same  strength  (ten  per  cent.),  the  amount 
of  solution  used  being  equal  to  the  amount  of  material  to  be  disin- 
fected. 

It  will  be  best  to  burn  cloths  used  to  wipe  away  the  discharges  of  the 
sick,  and  especially  those  used  in  wiping  away  the  infectious  material 
from  the  mOuth  and  nostrils  of  patients  with  diphtheria  or  scarlet  fever. 
Bits  of  old  muslin  may  be  used  for  this  purpose,  and  should  at  once  be 
thrown  upon  an  open  fire  or  gas  stove  aranged  in  the  fire-place  for  this 
purpose. 

Infected  sputum  may  be  discharged  directly  into  a  cup  half  full  of  the 
solution  of  chloride  of  lime  recommended  for  excreta,  or  of  Labar- 
raque's  solution. 


DISINFECTION.  21 

Handkerchiefs,  napkins,  and  towels  used  in  wiping  away  infectious 
discharges,  if  worth  preserving,  should  be  at  once  immersed  in  one  of 
the  following  solutions  :  Chloride  of  lime,  2  per  cent. ;  carbolic  acid,  2 
per  cent. ;  mercuric  chloride,  0.1  per  cent.  (=1  :  1000). 

"Cloths  used  for  washing  the  general  surface  of  the  body  should  also 
be  disinfected  with  one  of  the  above  mentioned  solutions ;  and  attend- 
ants should  invariably  disinfect  their  hands  by  washing  them  in  one  of 
these  solutions,  when  they  have  been  soiled  by  the  discharges  of  the 
sick. 

Disinfection  of  the  Person.  Labarraque's  solution,  diluted  with 
twenty  parts  of  water,  is  a  suitable  disinfecting  solution  for  bathing 
the  entire  surface  of  the  body  of  the  sick,  of  convalescents,  or  of  those 
whose  duties  take  them  into  the  sick-room ;  or  a  2  per  cent,  solution  of 
carbolic  acid,  may  be  used,  or  a  solution  of  mercuric  chloride  (corrosive 
sublimate)  of  1  :  1000.  The  poisonous  nature  of  this  solution  must  be 
kept  in  mind. 

The  International  Sanitary  Conference  of  Rome  gives  the  following 
directions  with  reference  to  the  disinfection  of  the  body  after  death 
from  cholera : 

"The  body  should  be  enveloped  in  a  sheet  saturated  with  one  of  the 
strong  disinfecting  solutions,1  without  previous  washing,  and  should 
at  once  be  placed  in  a  coffin." 

We  see  no  objection  to  washing  the  body,  if  the  strong  solution  of 
chloride  of  lime  is  used  for  this  purpose.  Washing  with  water  would 
necessitate  the  careful  disinfection  of  the  water  and  cloths  used  for  this 
purpose,  and  of  the  hands  of  the  attendants.  As  the  odor  of  chlorine  or 
of  carbolic  acid  would  be  objectionable  under  certain  circumstances, 
we  see  no  good  reason  for  insisting  upon  the  use  of  these  agents,  rather 
than  on  the  odorless  solution  of  mercuric  chloride,  which,  in  the  pro- 
portion of  1  :  1000,  would  no  doubt  be  equally  effective.  But  when 
there  is  an  odor  of  decomposition  to  be  neutralized,  the  solution  of 
chloride  of  lime  will  have  a  decided  advantage  on  account  of  its  de- 
odorizing properties. 

Disinfection  of  Clothing  and  Bedding.     The  cheapest  and  best  way  of 
disinfecting  clothing  and  bedding,  which  is  not  injured  by  the  ordinary 
operations  of  the  laundry,  is  to  immerse  it  in  boiling  water  for  half  an 
hour  or  longer.     It  should  be  placed  in  boiling  water  as  soon  ;is 
moved  from  the  person  <>r  the  bed  of  the  sick,  and  if  it  is  :  .   to 

remove  the  articles  from  the  room  in  order  to  accomplish  this,  they 
should  be  wrapped  in  a  sheet  or  towel  thoroughly  saturated  with  a  d 
infecting  solution,     if  it   is  impracticable  to  disinfect   such   infected 

clothing  and  bedding  immediately  by  boiling,  it  will  he  necessary  to  im- 
l  Chlortd*  of  lima,  4  par  c«nt.,  <>t. 


22  DISINFECTION. 

merse  it  in  one  of  the  following  disinfecting  solutions,  in  which  it 
should  be  left  for  four  hours :  Mercuric  chloride,  1  :  2000 ;  or  the 
"blue  solution,"1  of  this  salt  and  sulphate  of  copper,  diluted  by  adding 
two  fluid  ounces  of  the  concentrated  solution  to  a  gallon  of  water ;  or  a 
2  per  cent,  solution  of  carbolic  acid.  The  solution  of  chlorinated  lime 
(2  per  cent.)  may  also  be  used,  but  we  give  the  precedence  to  the  first 
mentioned  solutions,  because  of  the  bleaching  properties  of  this  solu- 
tion. The  blue  solution  does  not  injure  clothing,  and  is  to  be  preferred 
for  domestic  use  to  a  simple  solution  of  corrosive  sublimate,  which  in 
the  concentrated  form  is  highly  poisonous,  and  without  odor  or  color. 
When  diluted  as  directed,  this  solution  may,  however,  be  used  without 
great  danger.  The  metallic  taste  of  the  diluted  solution  could  scarcely 
fail  to  prevent  a  fatal  dose  from  being  swallowed  accidentally. 

Woolen  garments  and  other  articles  which  would  be  seriously  in- 
jured by  immersion  in  boiling  water,  or  in  one  of  the  disinfecting  so- 
lutions above  mentioned,  should  be  disinfected,  in  a  properly  con- 
structed disinfection  chamber,  by  steam  or  by  formaldehyd  gas. 

Exposure  to  steam  at  100°  C.  (212°  Fahr.)  for  half  an  hour  would  be 
equivalent  to  exposure  in  boiling  water  for  the  same  time,  if  the  cloth- 
ing is  hung  up  in  such  a  manner  as  to  be  fairly  brought  under  the  action 
of  the  disinfecting  agent.  To  be  certain  that  the  steam  does  not  fall 
below  this  temperature  in  the  disinfection  chamber,  a  thermometer 
must  be  placed  in  a  corner  of  the  room,  at  a  distance  from  the  point  of 
entrance  of  the  steam,  or  "  -  an  aperture  from  which  the  steam  escapes. 
This  should  mark  at  least  100°  C.  for  half 'an  hour  before  the  disinfec- 
tion can  be  considered  complete.2  To  accomplish  this,  it  is  evident 
that  the  steam  must  come  from  the  generator  at  a  higher  temperature, 
or,  in  other  words,  must  be  under,  pressure. 

It  must  be  remembered  that  in  a  majority  of  the  infectious  diseases 
in  which  disinfection  is  most  frequently  required  the  specific  germ  does 
not  form  resistant  spores  (cholera,  typhoid  fever,  tuberculosis,  diph- 
theria, erysipelas,  pneumonia,  yellow  fever,  smallpox).  In  these  dis- 
eases therefore  it  would  be  a  mistake  to  forbid  the  use  of  carbolic  acid, 
sulphur  dioxid,  and  other  agents  which  enjoy  the  confidence  of  sani- 
tarians, and  which  have  been  proved  by  laboratory  experiments  to 
destroy  pathogenic  organisms,  in  the  absence  of  spores. 

As  disinfection  by  steam  injures  certain  articles,  dry  heat  may  be 
used  as  a  substitute  for  moist  heat,  but  in  this  case  a  temperature  of  at 
least  110°  C.  (230°  Fahr.),  maintained  for  two  hours,  will  be  required. 

l  Bichloride  of  mercury 4  oz. 

Sulphate  of  Copper 1ft. 

Water 1  gal. 

8  The  committee  on  disinfectants  of  the  International  Sanitary  Conference  of  Rome  fixes 
one  hour  as  the  time  during-  which  steam  should  be  made  to  pass  over  articles  to  be  dis" 
infected. 


DISINFECTION.  23 

In  the  use  of  dry  heat,  even  greater  care  is  necessary  that  the  articles  to 
be  disinfected  are  freely  exposed, — that  is,  not  placed  in  the  oven  in 
bundles,  or  piled  one  upon  another,  but  freely  suspended  in  the  disin- 
fecting chamber.  For  it  has  been  shown  by  carefully  conducted  ex- 
periments that  the  penetrating  power  of  dry  heat  is  very  slight.  A 
properly  constructed  disinfection  oven,  such  as  that  of  Ransom,1  will 
be  required  if  dry  heat  is  to  be  used.  But  it  will,  as  a  rule,  be  preferable 
to  disinfect  such  articles  in  a  steam  disinfecting  chamber  of  modern 
construction  in  which  provision  is  made  for  exhausting  the  air  before 
steam  under  high  pressure  is  admitted,  and  in  which  after  disinfection 
the  clothing  is  rapidly  dried  before  being  removed  from  the  steam 
chamber. 

Sulphur  dioxid  is  a  less  reliable  disinfectant  than  steam  or  dry  heat, 
but  when  the  necessary  conditions  are  observed  there  is  no  doubt  of  its 
utility ;  and  the  fact  that  it  does  not  kill  the  spores  of  anthrax  and  of 
other  bacilli  is  no  reason  for  rejecting  an  agent  which  has  been  dem- 
onstrated by  experience  to  be  one  of  great  value,  which  has  been 
proved  by  laboratory  experiments  to  be  fatal  to  pathogenic  organisms 
in  the  absence  of  spores,  and  to  destroy  the  infecting  power  of  vaccine 
virus.  But  in  using  this  agent  the  conditions  of  successful  disinfection, 
which  have  been  established  by  experiment,  should  be  borne  in  mind. 
The  room  which  is  to  serve  as  a  disinfecting  chamber  must  be  very 
thoroughly  c1osed  :  every  crevice  and  key-hole  should  be  carefully 
closed  by  fastening  paper  over  it.  Even  this  precaution  will  not 
prevent  the  rapid  escape  of  gas  from  cracks  around  doors,  windows, 
etc.  It  is  therefore  desirable,  when  practicable,  to  use  a  disinfect- 
ing chamber  which  can  be  hermetically  closed.  The  articles  to  be 
disinfected  must  be  very  freely  exposi  d,  and  should  never  be  thrown 
into  the  room  in  bundles,  or  piled  one  upon  another.  We  concur  in 
the  recommendations  of  the  committee  on  disinfectant-  of  the  Ameri- 
can Public  Health  Association,  as  to  the  amount  of  sulphur  which 

mid  be  burned,  and  the  method  of  effecting  its  complete  combus 
tion: 

"To  secure  any  result  of  value,  it  will  be  necessary  to  close  the  apart- 
ment to  be  disinfected  as  completely  as  possible,  by  stopping  all  aper- 
tures  through  which    gas    might    escape,  and   to  barn  at  least    three 
pounds  of  sulphur  for  each  thousand  cubic  feel  of  air-space  in  the 
mi.     To  secure  complete  combustion  ulphur,  it  should  be 

placed,  in  powder  or  in  small  fragments,  in  a  shallow  iron  pan.  which 
should  be  set  upon  a  couple  of  bricks  in  a  tub  partly  filled  with  water. 


24  DISINFECTION. 

to  guard  against  fire.  The  sulphur  should  be  thoroughly  moistened 
with  alcohol  before  igniting  it."1  ' 

Since  the  above  was  written  with  reference  to  disinfection  by  sul- 
phur dioxid  (SO2)  the  valuable  germicidal  properties  of  formaldehyd 
gas  have  been  demonstrated,  and  satisfactory  methods  of  .generating 
this  gas  for  purposes  of  disinfection  have  been  devised.  Owing  to  its 
superior  germicidal  value  and  non-toxic  properties  it  has  to  a  con- 
siderable extent  taken  the  place  of  sulphur  dioxid  as  a  gaseous  disin- 
fectant. In  making  practical  use  of  this  agent  a  suitable  apparatus 
will  be  required.  For  the  disinfection  of  a  room  with  its  contents, 
freely  exposed  for  surface  disinfection,  one  pound  of  formalin  should 
be  volatilized  for  each  thousand  cubic  feet  of  air-space — the  time  of 
exposure  to  the  disinfecting  action  of  the  gas  being  not  less  than  twelve 
hours.  When  paraform  is  used  the  amount  required  will  be  60  grams 
to  1,000  cubic  feet  (Novy).  In  the  absence  of  any  apparatus  satisfac- 
tory results  have  been  obtained  by  the  Department  of  Health  of  city  of 
Chicago,  as  follows : 

"Ordinary  bed  sheets  were  employed  to  secure  an  adequate  evapo- 
ratory  surface,  and  these,  suspended  in  the  room,  were  simply  sprayed 
with  a  40  per  cent,  solution  of  formalin  through  a  common  watering 
pot  rose-head.  A  sheet  of  the  usual  size  and  quality  will  carry  from 
150  to  180  cc.  of  the  solution  without  dripping,  and  this  quantity  has 
been  found  sufficient  for  the  disinfection  of  1,000  cubic  feet  of  space. 
Of  course,  the  sheets  may  be  modified  to  any  necessary  number. 
*  *  *  Surface  disinfection  was  thorough,  while  a  much  greater 
degree  of  penetration  was  shown  that  that  secured  by  any  other 
method." 

Formalin  may  also  be  used  in  the  disinfection  of  rooms  and  their 
contents  by  spraying  all  exposed  surfaces. 

Experiments  made  by  Kinyoun  and  others  show  that  formalde- 
hyd gas  does  not  injure  the  color  or  textile  strength  of  fabrics  of  wool, 
silk,  cotton  or  linen  and  that  it  has  no  injurious  action  upon  furs, 
leather,  copper,  brass,  nickel,  zinc,  polished  steel  or  gilt  work.  Iron 
and  unpolished  steel  are  attacked  by  the  gas. 

We  would  remark,  that  in  the  absence  of  suitable  appliances  for 
disinfection,  and  in  general  when  the  disinfected  articles  are  of  little 
value,  consumption  by  fire  furnishes  the  readiest  and  safest  method  of 
disposing  of  such  articles. 

For  articles  of  value,  such  as  upholstered  furniture,  etc.,  which 
would  be  injured  by  any  of  the  processes  heretofore  recommended, 
free  exposure  to  the  air  (aeration)  for  three  or  four  weeks  is  directed 
by  the  Committee  on  Disinfectants  of  the  International  Sanitary  Con- 
ference of  Rome.     The  same  committee  directs  that  "objects  made 

1  Preliminary  report,  1.  c,  p.  427. 


DISINFECTION.  25 

of  leather,  such  as  trunks,  boots,  etc.,  should  be  destroyed  or  washed 
several  times  with  one  of  the  weak  disinfection  solutions," — carbolic 
acid  2  per  cent.,  or  chloride  of  lime  1  per  cent. 

The  means  heretofore  recommended  for  the  disinfection  of  woolen 
clothing,  blankets  and  similar  articles  will  not  be  sufficient  for  soiled 
mattresses.  As  a  rule,  they  should  be  opened,  and  the  contents  disin- 
fected by  steam,  with  subsequent  free  aeration,  and  the  cover  should 
be  washed  in  boiling  water  after  treatment  with  a  disinfecting  solution. 

Finally,  the  valuable  germicidal  properties  of  direct  sunlight  have 
been  demonstrated  by  numerous  carefully  conducted  experiments  and 
the  time-honored  domestic  practice  of  hanging  infected  clothing  and 
bedding  in  the  "open  air"  is  to  be  recommended.  This  should  supple- 
ment disinfection  by  formaldehyd  or  sulphur  dioxid. 

Disinfection  of  the  Sick-Room.  Every  effort  should  be  made  to  pre- 
vent a  room  occupied  by  patients  sick  with  an  infectious  disease  from 
becoming  infected.  Carpets,  stuffed  furniture,  curtains  and  other  arti- 
cles difficult  to  disinfect,  should  be  removed  at  the  outset.  Indeed, 
nothing  should  be  left  in  the  room  which  is  not  absolutely  required, 
and  all  furniture  and  utensils  should  be  of  such  a  character  that  they 
can  be  readily  disinfected  by  washing  with  boiling  water  or  with  a  dis- 
infecting solution.  Abundant  ventilation  and  scrupulous  cleanliness 
should  be  maintained,  and  a  disinfecting  solution  should  always  be  at 
hand  for  washing  the  floor,  or  articles  in  use,  the  moment  they  are 
soiled  by  infectious  discharges.  For  this  purpose  a  solution  of 
chloride  of  lime  may  be  used  (4  per  cent.). 

It  is  impracticable  to  destroy  infectious  material  in  an  occupied 
apartment  by  means  of  gases  <  r  volatile  disinfectants,  for  to  be  effective 
these  must  be  used  in  a  degree  of  concentration  which  would  make  the 
atmosphere  of  a  r  om  quite  irrespirable.  These  agents  are  therefore 
useful  only  as  deodorants.  They  are  all  more  or  less  offensive  to  the 
sick,  and  will  seldom  be  required,  even  as  deodorants,  when  proper 
attention  is  paid  to  cleanliness  and  ventilation. 

Daily  wiping  of  all   surfaces — floors,  walls,  and    furniture — with   a 
cloth  wet  with  a  disinfecting  solution,  is  to  l>c  recommended.     For 
this  purpose  a  dilution  of  chloride  of  lime  (2  per  cent.),  or  of  carl" 
acid  (2  per  cent. i,  or  mercuric  chloride  ( 1   :  L000),  may  In-  used. 

By  such  precautit  ms  as  ha\  e  been  indicated,  th<  >n  ol  the  sick- 

room may  b  nted,  especially  in  those  diseases,  such  as  chol 

and  typhoid  f<  ver,  in  which  the  infectious  agent  is  not  given  off  in  the 
br<  ath,  or  fr<  m  the  general  surface  of  the  body,  of  the  sick  person.  In 
smallpox  and  in  scarlet  fever  there  is  greater  danger  that  the  infecti 

nt  may  remain  attached  to  the  surfaces  in  the  room  :  for  the  atmos- 
phere becomi  -  infected  from  parti  en  <  iff  from  tl  e  of  the 
patient's  bod 


26  DISINFECTION. 

As  already  stated,  the  atmosphere  cannot  be  disinfected  while  the 
room  is  occupied.  There  is  much  less  reason  for  disinfecting  it  when 
the  patient  has  been  removed,  and  it  is  much  simpler  to  renew  it  by 
throwing-  open  the  doors  and  windows  than  to  attempt  to  disinfect  it. 
Indeed,  there  will  be  no  infectious  particles  to  destroy,  except  such  as 
are  dislodged  from  surfaces,  window  ledges,  etc.,  where  they  have 
settled  as  dust  while  the  room  was  occupied ;  and  if  the  precautions 
above  recommended  have  been  taken,  the  danger  of  such  reinfection 
of  the  atmosphere  will  be  reduced  to  a  minimum. 

Disinfection  of  the  vacated  room,  then,  consists  in  the  destruction  of 
all  infectious  particles  which  remain  attached  to  surfaces,  or  lodged  in 
crevices,  in  interstices  of  textile  fabrics,  etc.  The  object  in  view  may 
be  accomplished  by  thorough  washing  with  one  of  the  disinfecting 
solutions  heretofore  recommended ;  but  most  sanitarians  think  it  ad- 
visable to  "disinfect  the  room"  with  a  gaseous  disinfectant,  such  as 
formaldehyd  or  sulphur  dioxid.  If  the  "fumigation"  with  sulphur 
dioxid  is  resorted  to,  the  directions  given  by  the  Committee  on  Dis- 
infectants of  the  American  Public  Health  Association  should  be  fol- 
lowed, i.  e.,  three  pounds  of  sulphur  should  be  burned  for  every  1,000 
cubic  feet  of  air-space.  But,  as  already  stated,  disinfection  with  for- 
maldehyd gas  is  to  be  preferred  (see  page  15). 

At  the  end  of  from  twelve  to  twenty-four  hours,  doors  and  windows 
should  be  opened,  and  the  room  freely  ventilated.  After  this  fumiga- 
tion, all  surfaces  should  be  washed  with  a  disinfecting  solution  (chlor- 
ide of  lime  2  per  cent.,  carbolic  acid  2  per  cent.,  or  mercuric  chlorid 
1 :1000),  and  afterwards  thoroughly  scrubbed  with  soap  and  hot  water. 
Plastered  walls  should  be  white-washed. 

Disinfection  of  Privy  Vaults,  Cesspools,  etc.  The  contents  of  privy 
vaults  and  cesspools  should  never  be  allowed  to  accumulate  unduly,  or 
to  become  offensive.  By  frequent  removal/ and  by  the  liberal  use 
of  antiseptics,  such  necessary  receptacles  of  filth  should  be  kept  in  a 
sanitary  condition.  The  absorbent  deodorants,  such  as  dry  earth  or 
pounded  charcoal, — or  the  chemical  deodorants  and  antiseptics,  such 
as  chloride  of  zinc,  sulphate  of  iron,  etc., — will,  under  ordinary  cir- 
cumstances, prevent  such  places  from  becoming  offensive.  Disinfec- 
tion will  only  be  required  when  it  is  known,  or  suspected,  that  in- 
fectious material,  such  as  the  dejections  of  patients  with  cholera,  yel- 
low fever,  or  typhoid  fever,  has  been  thrown  into  the  receptacles. 

In  the  Manual  for  the  Medical  Department  of  the  U.  S.  Army  the 
following  directions  are  given : 

92.  When  accumulations  of  organic  material  undergoing  decompo- 
sition cannot  be  removed  or  buried,  they  may  be  treated  with  an  anti- 
septic solution,  or  with  freshly  burned  quicklime.     Quicklime  is  also  a 


DISINFECTIOA.  27 

valuable  disinfectant,  and  may  be  substituted  for  the  more  expensive 
chlorid  of  lime  for  disinfection  of  typhoid  and  cholera  excreta,  etc.  For 
this  purpose  freshly  prepared  milk  of  lime  should  be  used,  containing 
about  1  part,  by  weight,  of  hydrate  of  lime,  to  8  of  water. 

93.  During  the  prevalence  of  an  epidemic,  or  when  there  is  reason 
to  believe  that  infectious  material  has  been  introduced  from  any 
source,  latrines  and  cesspools  may  be  treated  with  milk  of  lime,  in  the 
proportion  of  5  parts  to  100  parts  of  the  contents  of  the  vault,  and  the 
daily  addition  of  10  parts  for  100  parts  of  daily  increment  of  feces. 

Hospitals.  The  directions  already  given  in  regard  to  disinfection  of 
the  sick-room  and  its  contents  apply  as  well  to  hospital  wards  in  which 
patients  with  infectious  diseases  are  treated.  In  addition  to  this,  it  will 
be  necessary  in  hospitals  to  guard  against  such  infectious  diseases  as 
erysipelas,  septicaemia,  puerperal  fever,  and  hopital  gangrene.  The 
antiseptic  treatment  of  wounds,  in  connection  with  a  proper  regard  for 
cleanliness  and  ventilation,  has  practically  banished  these  diseases  from 
well  regulated  hospitals.  Of  the  first  importance  in  effecting  this  are 
the  precautions  now  taken  with  reference  to  the  disinfection  of 
sponges,  instruments,  the  hands  of  attendants,  etc. 

Instruments  of  silver,  such  as  probes  and  catheters,  may  be  disin- 
fected by  passing  them  through  the  flame  of  an  alcohol  lamp.  In- 
struments of  steel,  gum  catheters,  etc.,  may  be  disinfected  by  immer- 
sion in  a  five  per  cent,  solution  of  carbolic  acid,  or  in  a  1 :1000  solution 
of  mercuric  chloride.  For  instruments  and  vessels  of  copper,  brass, 
and  tin,  boiling  water,  or  the  carbolic  acid  solution,  may  be  used. 
Vessels  of  porcelain  or  glass  may  be  disinfected  by  heat,  or  by  either  of 
the  disinfecting  solutions  mentioned.  Sponges  should  be  kept  per- 
manently in  one  of  the  disinfecting  solutions,  or,  what  is  hotter,  may  be 
dispensed  with  entirely  for  the  cleansing  of  wounds.  In  place  of  them, 
irrigation  with  a  disinfectant  solution  may  he  resorted  to,  or  the 
charges  may  be  wiped  away  with  some  cheap  absorbent  material  which 
can  be  burned  after  having  been  once  used 

Patients  in  hospitals,  with  infectious  diseases,,  will  of  course  be  kept 
in  isolated  wards.      Everything  winch  comes  from  such  a  ward  should 
be  disinfected,  and  the  immediate  attendants  of  the  sick  should  not 
allowed  to  visit  other  parts  of  the  hospital  without  first  changing  their 
outer  clothing  for  a  r<  cently  disinfected  suit,  and  washing  their  hands 
in  a  disinfecting     olution.     When   relieved   from   duty   their  un 
clothing  should  also  be  disinfected;  and  they  should  I 
bath  with  one  of  the  weak  disinfecting  solutions  h 
mended. 

Disinfection    of    Water   and    Articles   of    Food.     The    disiir 
drinking-water  on  a  large  scale,  in  reservoirs,  wells,  etc.,  ia  imprad 


28  DISINFECTION. 

ble.  But  it  is  a  very  simple  matter  to  disinfect  water  which  is  sus- 
pected of  being  contaminated  with  the  germs  of  cholera,  typhoid  fever, 
or  any  other  disease  transmissable  in  this  way.  This  is  readily  ac- 
complished by  boiling.  As  already  stated,  all  known  disease  germs 
are  destroyed  by  the  boiling  temperature  maintained  for  half  an  hour. 
The  importance  of  this  precaution  during  the  prevalence  of  an  epi- 
demic of  cholera  or  of  typhoid  fever  cannot  be  over-estimated,  when 
the  water  used  for  drinking  purposes  comes  from  an  impure  source,  or 
is  liable  to  contamination  by  discharges  of  patients  suffering  from 
these  diseases.  Those  articles  of  food,  and  especially  milk,  animal 
broths,  etc.,  which  might  serve  as  pabulum  for  disease  germs,  should, 
during  the  prevalence  of  an  epidemic,  be  cooked  but  a  short  time  be- 
fore they  are  eaten.  And  such  food,  if  put  aside  for  hours  after  it  has 
been  prepared,  should  always  be  again  subjected  to  a  boiling  tempera- 
ture shortly  before  it  is  served.  Food  which  gives  evidence  of  com- 
mencing putrefaction  is  unfit  for  use,  and  in  time  of  epidemics  is  es- 
pecially dangerous. 

Disinfection  of  Ships.  It  should  be  the  aim  of  a  physician  attached 
to  a  passenger  ship,  or  of  the  master  of  a  vessel  having  no  physician  on 
board,  to  prevent  the  vessel  from  becoming  infected  when  in  an  in- 
fected port,  or  when  cases  of  infectious  disease  occur  on  board.  This 
is  to  be  accomplished  by  keeping  the  ship  clean ;  by  disinfecting  sus- 
pected articles,  and  especially  the  soiled  clothing  of  passengers,  before 
they  are  received  on  board ;  by  the  isolation  of  cases  of  infectious  dis- 
ease which  occur  on. board;  and  by  the  thorough  execution  of  those 
measure  of  disinfection  recommended  for  the  sick-room.  When  a 
case  of  cholera  or  of  yellow  fever  occurs  upon  a  ship  at  sea,  it  cannot 
be  taken  as  evidence  that  the  vessel  is  infected  unless  at  least  five  days 
have  elapsed  since  the  person  attacked  came  on  board.  For  he  may- 
have  contracted  the  disease  from  exposure  at  the  port  of  departure, 
or  in  some  other  locality  on  shore.  When,  however,  a  longer  time 
than  this  has  elapsed,  or  when  several  cases  develop  in  a  particular 
locality  on  ship-board,  either  simultaneously  or  successively,  the  ves- 
sel must  be  considered  infected,  unless  it  is  shown  that  the  cases  are 
directly  due  to  the  opening  of  baggage  containing  infected  clothing. 

In  practice,  the  sanitary  officials  at  the  port  of  arrival  usually  treat 
a  vessel  as  infected  if  any  case  of  infectious  disease  has  occurred 
upon  her  during  the  voyage.  This  is  a  safe  general  rule,  which  should 
not  be  departed  from  unless  a  considerable  time — five  or  seven  days — 
has  elapsed  since  the  cases  occurred,  and  they  can  be  clearly  traced  to 
exposure  before  coming  on  board.  In  this  case,  if  the  ship  is  clean 
and  the  precautions  relating  to  disinfection  and  isolation  of  the  sick 
have  been  faithfully  executed,  the  health  officer  may  be  justified  in  dis- 


DISINFECTION.  29 

pensing  with  the  general  measures  of  disinfection  which  are  required 
for  an  infected  ship. 

These  measures  do  not  differ  from  those  heretofore  recommended 
for  the  disinfection  of  the  sick-room  and  its  contents ;  but  the  special 
conditions  on  ship-board,  and  the  great  interests  at  stake,  make  it  es- 
sential that  the  execution  of  these  measures  should  be  in  the  hands 
of  sanitary  experts. 

In  the  disinfection  of  ships,  fumigation  with  sulphurous  acid  gas 
has  been  largely  practiced  by  those  in  charge  of  quarantine  establish- 
ments. The  fact  that  the  ship  may  be  almost  hermetically  closed,  and 
the  escape  of  gas  to  a  great  extent  prevented,  makes  this  method  of 
disinfection  more  trustworthy  than  in  the  case  of  dwellings  and  hos- 
pitals. The  further  fact,  that  certain  parts  of  the  ship  are  inaccessible 
for  the  application  of  disinfecting  solutions,  seems  to  make  the  use  of  a 
gaseous  disinfectant  imperative. 

Disinfection  by  means  of  steam,  especially  of  an  iron  vessel,  would 
no  doubt  be  a  difficult  matter  on  account  of  the  condensation  which 
would  occur  from  contact  with  the  cool  walls  of  the  vessel  below  the 
water-line.  But  it  will  be  well  to  fill  the  vessel  with  steam  before  in- 
troducing the  sulphur  dioxid ;  for,  as  already  stated,  the  disinfecting 
power  of  this  agent  is  much  greater  in  presence  of  moisture.  A  well 
equipped  quarantine  establishment  should  have  an  apparatus  for  gen- 
erating sulphurous  acid  gas,  and  injecting  it  into  vessels,  as  this  is 
the  most  expeditious  and  satisfactory  method  of  fumigating  a  ship. 

An  essential  part  of  the  disinfection  of  a  ship  will  c< insist  in  the 
thorough  cleansing  of  the  bilge.  The  International  Sanitary  Confer- 
ence of  Rome  prescribed  that  the  bilge  water  shall  be  pumped  out  and 
replaced  by  sea  water  at  least  twice  at  each  disinfection  of  the  vessel. 

Merchandise.  Article  V,  of  the  Report  of  the  Committee  on  Disin- 
fection of  the  International  Sanitary  Conference  of  Rome,  says: 

"V.  Disinfection  of  merchandise  and  of  the  mails  is  unnecessary. 
(Steam  under  pressure  is  the  only  reliable  agent  f"r  the  disinfection 
of  rags — les  chiffons  en  ^ros.)" 

We  think  this  statement  too  broad,  especially  so  far  a-  merchandise 
is  concerned  which  has  been  on  hoard  a  ship  infected  'with  yellow 
fever.  The  poison  of  this  disease  seems  to  he  capable  of  self  -multipli- 
cation on  a  foul  ship  in  tropical  latitudes,  quite  independently  of  p 
sengers  and  crew.  And  there  is  ample  evidence  thai  even  when  no 
case  has  occurred  on  an  infected  shij  those  who  are  enga| 

in   discharging   her   cargo   after   arrival    in    port    may    he   seized    with 
yellow  fever  from  breathing  the  infected   atmosphere  of  the  hold 
Evidently  merchandise  conveyed  i  n  such  a  ship  should  he  disin 
But  it  does  not  seem  necessary  to  break  packages  which  h 


30  DISINFECTION. 

board  in  good  condition,  and  a  thorough  fumigation  with  sulphurous 
acid  gas  will  be  sufficient  if  the  unbroken  packages  are  so  distributed 
as  to  be  fairly  exposed  to  the  action  of  the  disinfecting  agent.  To  ac- 
complish this,  and  to  effectually  disinfect  the  ship,  it  will  be  necessary 
to  discharge  the  cargo  at  the  quarantine  station. 

The  collections  of  the  rag-man  cannot  properly  be  placed  in  the  same 
category  with  other  merchandise,  such  as  agricultural  products,  hard- 
ware, new  cotton  or  woolen  goods,  etc.  An  exception  with  regard  to 
rags  is  indicated,  but  not  stated  with  sufficient  precision,  in  the  article 
which  we  have  quoted.  There  is  evidence  that  smallpox  has  been  not 
infrequently  transmitted  in  rags,  and  sanitarians  are  generally  agreed 
that  it  would  be  very  imprudent  to  admit  rags  collected  in  or  shipped 
from  localities  infected  with  cholera  or  yellow  fever,  without  first  sub- 
jecting them  to  thorough  disinfection. 


PART  SECOND. 

INDIVIDUAL    PROPHYLAXIS    AGAINST    INFECTIOUS    DISEASES. 

The  state  establishes  quarantine  stations,  to  guard  against  the  intro- 
duction of  infectious  diseases  of  exotic  origin ;  and  in  enlightened 
countries,  sanitary  officials,  under  the  direction  of  the  central  govern- 
ment, or  of  states  and'  municipalities,  are  charged  with  the  duty  of 
guarding  the  public  against  such  diseases.  It  is  generally  recognized 
that  this  is  to  be  accomplished  by  the  isolation  of  the  sick,  the  use  of 
disinfectants,  and  by  general  measures  of  sanitary  police. 

One  way  in  which  the  individual  may  indirectly  protect  himself 
against  such  diseases  is  by  using  his  influence  to  have  this  sanitary 
service  placed  in  the  hands  of  competent  men,  and  in  sustaining  them 
in  their  efforts  to  exclude  or  stamp  out  infectious  diseases  by  such 
measures  as  have  been  demonstrated  by  science  and  experience  to  be 
efficient  for  this  purpose. 

But  this  is  not  the  kind  of  "individual  prophylaxis"  which  we  have 
to  consider  here.  The  question  is,  What  can  the  individual  do  to  pro- 
tect himself  and  those  immediately  dependent  upon  him,  under  the 
various  circumstances  in  which  he  may  be  placed,  and  especially  in 
the  presence  of  an  epidemic? 

As  the  advice  we  have  to  give  will  differ  greatly  according  to  the 
disease,  we  shall  pass  in  review  the  principal  infectious  maladies  of  man, 
and  shall  attempt  to  give  for  each  such  practical  instructions  as  will 
enable  an  intelligent  person  to  take  all  practicable  precautions  for  his 
own  protection,  and  for  that  of  his  immediate  family.  We  have  first, 
however,  to  make  some  general  remarks. 


DISINFECTION.  33 

Infectious  diseases  are  contracted  by  contact  with  the  sick,  through 
the  medium  of  infected  articles — "fomites" — or  by  exposure  in  infected 
localities. 

The  evident  general  rule  of  prophylaxis  is,  therefore,  to  avoid  all  of 
these  sources  of  infection ;  but  there  are  circumstances  in  which  this  is 
either  impossible  or  unjustifiable.  Duty  calls  the  physician  and  the 
nurse  into  the  sick-room,  and  no  argument  based  upon  self-protection 
can  keep  the  devoted  mother  from  the  bedside  of  her  sick  child,  or  the 
wife  from  giving  her  personal  attention  to  her  husband,  or  the  husband 
to  his  wife,  when  stricken  by  pestilence.  Humanity  requires  that  dur- 
ing an  epidemic  the  sick  shall 'be  cared  for,  the  dead  buried,  and  the 
foul  places  cleansed.  All  this  calls  for  the  active  and  intelligent  efforts 
of  persons  who  have  the  courage  to  face  danger,  and  not  only  of  those 
who  by  their  profession  are  necessarily  brought  in  contact  with  the 
sick — physicians,  clergymen,  sanitary  officials,  nurses — but  often,  also, 
of  volunteers;  for,  during  the  prevalence  of  an  epidemic  of  cholera, 
or  of  yellow  fever,  the  number  of  physicians  and  trained  nurses  within 
the  affected  area  is  commonly  insufficient  for  the  care  of  the  sick. 

The  history  of  epidemics  shows  that  brave  men  and  women  are  to 
be  found  in  every  civilzed  country,  who  are  willing  to  volunteer  for 
such  perilous  duties  ;  and  also  that  physicians,  and  those  whose  legiti- 
mate duty  it  is  to  care  for  the  sick,  very  rarely  desert  their  post  in  time 
of 'danger;  but  the  mortality  among  these  brave  men  and  women  who 
stand  by  their  guns,  and  among  the  volunteers  who  go  to  their  assist- 
ance, is  often  very  great.  There  is  a  wide-spread  notion  among  people 
not  familiar  with  the  facts,  that  doctors  enjoy  a  certain  immunity  from 
infectious  diseases  not  possessed  by  other  people,  and  that  the  absence 
of  fear  is  a  safeguard  .-(gainst  infection.  Such  a  supposition  is  with- 
out foundation,  and  is  an  insult  to  the  brave  nun  and  wmu/n  who  fall 
at  their  post  of  duty  in  ev<  ry  epidemic.  Courage  is  no  more  a  por- 
tion against  disease  germs  than  against  bullets.  It  is  true,  that  in  epi- 
demics, as  in  war,  the  sulkers  and  cowards  often  run  into  danger  which 
the  men  in  the  rank's  escape.  The  rashness  which  results  from  ignor- 
ance or  from  thoughtlessness  is  not  courage,  any  more  than  the  pru- 
dence which  avoids  danger  when  there  is  no  gi  on  for  facing  it  is 
cowardice.  Those  who  rashly  venture  within  the  lines  drawn  by  an 
epidemic,  in  the  pursuit  of  litis  i  pleasure,  on  the  supposition 
that  they  will  escape  the  prevailing  disease  because  they  are  "not 
afraid,"  often  fall  victims  to  their  unreasoning  temerity,  ami  not  infre- 
quently heat  a  hasty  retreat,  with  blanched  face,  when  they  are  brought 
directly  ipto  the  presence  of  the  sick  and  the  dying, 

Our  advice  t<>  the  brave  IS,    I'"  nol   put   YOUr  trust   in  your  k'^\- 
for  it  is  no  armor  againsl  infection.     Rely  rather  upon  t! 


32  DISINFECTION. 

tions  which  science  and  experience  indicate  as  best  suited  to  the 
special  circumstances  in  which  you  may  be  placed,  and  do  not  hesitate 
to  retreat  before  an  invisible  foe,  when  you  are  not  required  by  con- 
sideratons  of  duty  to  remain  upon  the  field  of  battle.  If  your  services 
are  not  required,  you  are  simply  in  the  way ;  and  if  you  fall  ill,  you  add 
to  the  labors  of  those  who  devote  themselves  to  the  care  of  the  sick. 
And  to  the  timid  we  would  say  let  not  your  fear  control  your  actions, 
but  look  the  circumstances  fairly  in  the  face,  and  be  guided  by  reason 
and  knowledge,  or  by  the  advice  of  those  competent  to  decide  for  you. 
A  premature  flight  may  bring  you  into  ridicule,  or  into  greater  dangers 
than  those  you  flee  from.  Do  not  let  your  fears  exaggerate  the  facts, 
and  weigh  these  in  the  balance  of  your  reason,  and  not  of  your  appre- 
hensions. The  fact  that  Judge  A  or  Col.  B  has  fallen  a  victim  to 
cholera  or  yellow  fever  is  no  more  reason  for  deserting  your  home 
than  is  the  fact  that  the  humblest  citizen  of  your  town  has  died  from 
the  same  disease. 

If  courage  is  no  protection  against  infection,  it  cannot  be  denied  that 
fear,  in  the  presence  of  the  infectious  agent,  is  a  predisposing  cause 
which  frequently  determines  an  attack,  and  which  may  turn  the  balance 
in  favor  of  a  fatal  result.  The  depressing  effect  of  fear  is  well  known, 
and  all  influences  which  reduce  the  vital  resisting  power  of  the  indi- 
vidual predispose  to  an  attack  when  an  epidemic  is  prevailing. 

Other  predisposing  causes  of  a  general  nature  are  those  conditions 
of  enfeebled  resistance  which  result  from  ill-health,  venereal  and  bac- 
chanalian excesses,  etc. 

Of  all  these,  it  is  probable  that  excessive  indulgence  in  intoxicating 
drinks  is  the  most  potent  factor  in  swelling  the  mortality  returns  dur- 
ing the  prevalence  of  pestilential  diseases.  This  predisposing  cause 
acts  in  several  different  ways.  The  individual  whose  reason  is  befud- 
dled by  drink,  stumbles  stupidly  into  all  kinds  of  danger.  He  is  "not 
afraid"  to  sleep  upon  the  ground,  exposed  to  the  night  air,  when  yellow 
fever  is  prevailing,  or  to  quench  his  thirst  with  water  which  a  prudent 
man  would  reject  as  unfit  to  drink  in  the  presence  of  cholera,  or  to 
wrap  himself  in  a  blanket  which  has  recently  been  in  use  by  a  patient 
with  smallpox.  Again,  the  debility,  often  attended  with  digestive  de- 
rangement, which  follows  a  recent  debauch,  constitutes  a  most  favora- 
ble condition  for  the  reception  of  the  germs  of  cholera,  of  yellow  fever, 
and  of  infectious  diseases  generally.  Those  who  use  intoxicating 
drinks  habitually,  but  within  the  limits  marked  by  that  mental  aberra- 
tion or  loss  of  reason  which  constitutes  intoxication,  are  less  subject  to 
infection  than  the  man  who  is  suffering  from  the  effects  of  a  recent 
"spree."  But  if  they  have  any  organic  disease  of  the  stomach,  the 
kidneys,  or  of  the  liver,  as  a  result  of  their  habits,  this  constitutes  a 


DISINFECTION.  33 

predisposition  to  be  attacked,  and  is  a  very  serious  complication  when 
an  attack  is  developed. 

Persons  suffering  from  chronic  wasting  diseases,  profuse  discharges, 
or  recent  hemorrhage,  are  especially  liable  to  become  the  victims  of  an 
infectious  disease  during  its  epidemic  prevalence.  The  same  is  true 
of  those  whose  vital  resistance  is  below  par  from  insufficient  food,  or 
from  the  continued  respiration  of  vitiated  air — crown  poisoning,  sewer- 
gas  poisoning,  etc 

In  addition  to  the  predisposing  causes  mentioned,  which  furnish  in- 
dications of  more  or  less  value  with  reference  to  individual  prophy- 
laxis, there  are  individual  and  race  differences  in  susceptibility  to  cer- 
tain diseases  manifested  by  those  who  are  in  perfect  health.  One  man 
may  be  repeatedly  exposed  to  an  infectious  disease  without  falling 
sick,  while  another  may  suffer  several  attacks  of  a  disease,  such  as 
smallpox,  in  which  one  attack  commonly  confers  immunity.  Race 
differences  in  susceptibility  are  shown  in  the  relative  immunity  of  the 
negro  from  the  effects  of  the  yellow  fever  poison,  and  the  great  suscep- 
tibility of  the  same  race  to  smallpox. 

We  shall  consider  in  detail  the  question  of  individual  prophylaxis 
against  certain  infectious  diseases,  which,  by  reason  of  their  fatality  and 
occasional  wide-spread  epidemic  prevalence,  seem  entitled  to  special 
attention  in  an  essay  of  this  nature. 

Cholera.  In  Asiatic  cholera  the  danger  of  infection  from  association 
with  the  sick,  in  the  capacity  of  nurse  or  physician,  is  very  slight.  This 
is  amply  demonstrated  by  experience.  On  the  other  hand,  laun- 
dresses, who  do  not  come  directly  in  contact  with  the  sick,  but  who 
handle  clothing  soiled  by  their  discharges,  are  liable  to  contract  the 
disease.  Ey  far  the  greater  number  of  cases,  however,  result  from 
exposure  in  infected  localities,  and  fn  >m  drinking  infected  water.  Out- 
side of  the  area  in  India  where  cholera  prevails  as  an  endemic  disease, 
localities  become  infected  and  the  water-supply  contaminated  as  a  re- 
sult of  the  introduction  of  infectious  material  from  previously  infected 
localities,  either  in  f  .mites,  or  through  the  medium  of  the  discharge* 
of  the  sick.  These  facts  furnish  the  indications  for  individual  as  well 
as  for  general  measures  of  prophylaxis. 

In  the  sick-room  the  precautions  to  be  taken  are,  to  keep  the  room 
clean  and  well  ventilated,  to  disinfect  the  discharges  of  the  sick  and  all 
soiled  articles  as  promptly  as  possible,  and  to  wash  the  hands  in  a 
infecting  solution  when  they  have  been  in  contact  with  the  patient 
with  soiled  clothing.  Attendants  should  not  take  their  food  in  the 
room  occupied  by  the  sick,  and  should  not  drink  liquids  which  have 
been  exposed  in  the  sick-room. 


34  DISINFECTION. 

The  general  directions  relating  to  diet,  drinking-water,  etc.,  which 
we  shall  shoitly  give,  apply  to  the  attendants  upon  the  sick,  as  well  as 
to  those  at  a  distance  from  them ;  and  it  should  be  remembered,  in  the 
interest  of  the  sick,  that  these  attendants  do  not  run  any  special  risks 
beyond  those  to  which  all  persons  within  the  area  of  infection  are  ex- 
posed. "  Indeed,  we  may  go  further,  and  say  that  they  run  far  less  risk 
when  they  are  in  a  well  regulated  hospital  and  under  intelligent  super- 
vision, than  do  those  persons  who  dwell  in  the  localities  outside  of  the 
hospital  from  which  the  cases  under  their  charge  have  come. 

Attendants  upon  the  sick  should  have  their  meals  at  regular  hours, 
should  not  be  deprived  of  a  fair  allowance  of  sleep,  and  should  never 
be  allowed  to  become  exhausted  by  protracted  vigils  or  excessive  fa- 
tigue. 

When  cholera  has  been  introduced  into  a  country  and  is  extending 
its  limits  from  day  to  day,  one  of  the  first  questions  which  will  pre- 
sent itself  to  those  who  are  able  to  change  their  place  of  residence  will 
be,  whether  they  shall  attempt  to  keep  out  of  its  way,  and  if  so,  where 
it  is  best  to  go.  The  answer  to  this  question  must  depend  very  much, 
upon  circumstances.  Those  who  are  unfortunate  enough  to  live  in  a 
city  or  town  which  has  a  bad  sanitary  record,  which  is  not  provided 
with  an  efficient  health  department,  or  does  not  provide  money  to  ena- 
ble the  officers  appointed  to  do  efficient  work,  had  better  decamp  in 
good  time,  so  as  to  evade  the  foe  entirely,  or  to  meet  it  upon  a  field  more 
favorable  for  defensive  operations.  There  should  be  no  stampede,  and 
no  running  away  in  haste  without  any  definite  idea  of  why  and  where. 
The  time  to  go  is  before  the  disease  has  fairly  obtained  a  lodgment. 
Consider  that  if  the  season  is  not  far  advanced,  and  the  town  is  in  an 
unfavorable  sanitary  condition,  there  is  every  reason  to  anticipate  that 
the  first  cases  will  be  followed  by  a  severe  epidemic,  and  decide  at  the 
outset  whether  you  will  put  your  castle  in  order  to  stand  a  siege,  trust-j 
ing  to  well  considered  measures  of  individual  prophylaxis,  or  whetherf 
you  will  beat  a  masterly  retreat  in  advance  of  the  first  assaults  of  th<* 
enemy.  Those  who  vacillate,  in  the  hope  one  day  that  the  epidemic  is 
on  the  decline,  and  in  the  fear  the  next  that  it  will  sweep  everything 
before  it,  in  the  end  very  often  stay,  when  they  could  just  as  well  havfi 
gone,  and  at  the  same  time  neglect  those  precautions  which  they^j 
should  have  taken  at  the  outset  if  they  had  decided  to  stay. 

To  those  who  are  unable  or  unwilling  to  desert  their  homes,  w 
would  say,  that  when  proper  precautions  are  taken  the  danger  is  reall; 
not  very  great,  and  that  sanitarians  look  for  the  day  when  cholera  wil 
be  practically  banished  from  civilized  countries.     See  that  your  prem-ij 
ises  are  in  good  sanitary  condition,  and  do  what  you  can  to  induce! 
your  neighbors  and  the  authorities  in  your  town  to  prepare  for  th  ' 


DISINFECTION.  35 

storm.  Look  especially  after  the  plumbing  of  your  houses,  and  if 
there  is  a  cesspool  or  privy  vault  upon  your  premises,  see  that  it  is 
kept  in  good  condition  by  the  use  of  antiseptics  and  deodorants.1 
Above  all,  see  that  no  food  comes  into  your  house  except  such  as  is 
sound  and  good,  and  that  the  drinking-water  used  by  your  family  is 
beyond  suspicion.  Well-water  is  always  open  to  suspicion,  and  in 
general,  during  the  prevalence  of  cholera,  it  will  be  advisable  to  boil 
all  water  used  for  drinking  purposes.  This  is  a  prophylactic  measure  of 
prime  importance,  and  there  is  good  reason  to  believe  that  if  faithfully 
executed  it  would,  to  a  great  extent,  limit  the  ravages  of  the  Asiatic 
pestilence.  Tea  and  coffee  recently  made  can  be  taken  with  impunity. 
Milk,  «during  the  prevalence  of  an  epidemic,  should  be  boiled  before  it 
is  used  as  food.  Mineral  waters,  if  bottled  at  places  distant  from  the 
infected  area,  may  be  drunk  in  moderation.  A  moderate  amount  of 
sound  wine,  which  was  bottled  prior  to  the  epidemic,  may  be  permitted 
to  those  who  are  in  the  habit  of  using  it.  Those  not  in  the  habit  of 
using  stimulants  should  not  resort  to  their  use  during  the  progress  of 
an  epidemic.  Those  accustomed  to  them  should  restrict  their  liba- 
tions within  moderate  limits,  and  will  find  a  little  brandy  and  soda,  or 
Apollinaris  water,  to  be  better  than  wines,  and  especially  than  the  acid 
wines,  which  are  apt  to  derange  the  digestion. 

Food  should  be  plain  and  well  cooked,  and  should  be  taken  in  mod- 
erate quantities.  Intemperance  in  eating  is  quite  as  bad  as  intemper- 
ance in  drinking.  Soups,  meats  and  vegetables  should  always  be 
served  hot,  and  should  not  be  put  aside  for  a  future  repast,  or,  if  served 
a  second  time,  should  be  brought  to  the  temperature  of  boiling  water 
shortly  before  they  are  eaten.  Pastry  and  rich  puddings,  and  all 
coarse  and  indigestible  meats  and  vegetables,  are  to  be  avoided. 
Sound,  ripe  fruit,  winch  lias  been  brought  to  the  house  with  the  outer 
skin  unbroken,  may  be  eaten  in  moderation  by  those  who  know  by  ex- 
perience that  it  agrees  with  ihem.  It  should  be  carefully  washed  he- 
it  is  eaten.  Melons,  <  ucumbers,  unripe  apples,  peaches,  or  pe 
acid  fruits  generally,  and,  in  short,  .all  those  articles  which  are  known 
to  give  rise  to  digestive  d  cuts  in  the  absence  of  cholera,  would 

ter  be  banished  from  the  supply-list  during  the  prevail  this 

ise. 

I  to  the  precautions  relating  ml  drink,  we  would 

those  relating  to  personal  habits  and  clothing.     '1  ' 

ted.  and,  <>n  the  I  (thet  hand,  84 

to  dian  I  ild  al  i  >i  tention.     1 1 

greatest  importance,  and.  inde  lual 

prophyl;  ht  diet,  and  a  d<  >se  or  tv. 


36  DISINFECTION. 

ciyne,  or  of  Hope's  mixture,  or  of  any  approved  combination  of  an 
opiate  and  an  astringent,  will  usually  suffice  to  control  a  slight  diar- 
rhoea, even  if  it  is  of  a  choleraic  character. 

The  clothing  should  be  suited  to  the  season,  but  great  care  must  be 
taken  that  it  is  warm  enough  at  all  times  to  prevent  the  body  from  be- 
coming chilled.  A  broad  flannel  belt  worn  about  the  abdomen  is  rec- 
ommended by  many  physicians  of  experience,  and  is  no  doubt  useful. 
Baths  should  be  taken  at  frequent  intervals,  but  should  not  be  too  pro- 
longed or  too  cold,  and  should  be  followed  by  a  vigorous  rubbing  of 
the  surface,  to  establish  reaction.  Excessive  exercise  and  fatiguing 
labor  of  all  kinds  are  to  be  avoided.  One  should  never  feel  "done  up," 
as  a  result  of  his  exertions  in  the  way  of  business  or  of  pleasure,  for  the 
lassitude  resulting  from  over-exertion,  like  that  which  results  from  fear, 
predisposes  to  an  attack.  Mental  depression  is,  so  far  as  possible,  to 
be  avoided ;  "grief,  despondency  and  "carking  care"  are  recognized  as 
predisposing  causes  in  cholera  and  in  other  infectious  diseases. 

The  use  of  "sulphuric  acid  lemonade" — that  is,  of  pure  water  acidu- 
lated with  this  acid  and  sweetened  to  taste — has  been  recommended  as 
a  prophylactic,  and  there  is  some  evidence  in  favor  of  its  usefulness. 
We  would  not  advise  its  indiscriminate  use,  or  that  of  any  other  pro- 
phylactic of  this  nature.  When  cholera  has  made  its  appearance  in  a 
dwelling  or  in  a  public  institution,  the  inmates  may  be  given  this,  to 
the  exclusion  of  all  other  drinks. 

Yellozv  Fever.  This  disease,  like  cholera,  is  contracted  in  infected 
localities,  rather  than  by  contact  with  the  sick.  Indeed,  it  is  rarely,  if 
ever,  communicated  directly  by  a  sick  person  to  his  attendants.  In  in- 
fected places  the  poison  seems  to  be  given  off  from  the  soil,  or  from  col- 
lections of  decomposing  organic  matter,  and  we  ha\e  no  definite  evi- 
dence that  it  is  communicated  through  the  medium  of  food  or  drink- 
ing-water. The  history  of  epidemics  of  this  disease  shows  that  when 
it  obtains  a  lodgment  in  a  city  or  town  which  is  in  an  insanitary  condi- 
tion, in  southern  latitudes  and  during  the  summer  months,  it  extends 
its  area  and  invades  new  localities  similarly  situated,  until  frost  occurs, 
or  at  least  until  the  weather  becomes  comparatively  cool  in  the  autumn. 
Those  who  remain  in  an  infected  area,  unless  protected  by  a  previous 
attack,  are  almost  certain  to  contract  the  disease,  and  much  less  can 
be  done  in  the  way  of  individual  prophylaxis  than  in  cholera.  We 
therefore  advise  all  those  who  can  get  out  of  the  way  of  this  fatal  dis- 
ease to  do  so.  As  a  rule,  there  will  be  plenty  of  time,  after  there  is 
evidence  that  the  disease  has  established  itself  in  certain  parts  of  a  city, 
for  those  who  live  at  a  little  distance  from  these  centers  of  infection 
to  get  away,  in  a  deliberate  and  well  considered  manner.  The  occur- 
rence of  one  or  more  imported  cases  cannot  be  taken  as  evidence  that 


DISINFECTION.  37 

an  epidemic  will  follow,  and  is  no  reason  for  deserting  one's  home.  If 
proper  precautions  are  taken  by  the  sanitary  authorities,  it  is  very 
probable  that  no  evil  result  will  follow  such  importation  of  the  disease. 
But  when  these  imported  cases  are  followed  by  the  occurrence  of  other 
cases  in  the  vicinity  where  they  have  been  sick,  or  when  such  local 
cases  occur  in  the  vicinity  of  wharves  where  vessels  from  infected  ports 
discharge  their  cargoes,  or  in  sailors'  boarding-houses,  etc.,  it  must 
be  taken  as  evidence  that  the  disease  has  effected  a  lodgment,  and  that 
infected  centers  have  been  established,  from  which  an  epidemic  will  in 
all  probability  be  developed,  if  the  season  is  favorable  and  the  city  in  an 
insanitary  condition. 

An  epidemic  is  not  developed  so  rapidly  as  in  the  case  of  cholera,  but 
the  disease  usually  extends  its  limits  in  a  very  deliberate  way,  and  while 
it  is  chiming  its  victims  in  one  section  of  a  city,  other  sections  in  the 
immediate  vicinity  might  be  quite  healthy.  But  the  territory  invaded 
remains  infected  until  cold  weather  puts  an  end  to  the  epidemic.  Fre- 
quently it  happens  that  no  new  cases  occur  in  an  infected  area  for  sev- 
eral weeks,  or  even  months,  for  the  simple  reason  that  all  those  who  re- 
mained to  do  battle  with  the  pestilence  have  suffered  an  attack  or  are 
protected  by  a  previous  attack.  The  epidemic  has  ceased  for  want  of 
material,  but  the  infection  remains,  and  will  manifest  itself  if  unpro- 
tected persons  venture  within  the  infected  area  from  a  mistaken  idea 
that  there  is  no  more  danger  because  there  are  no  longer  any  cases. 

In  this  disease,  then,  the  most  important  point  in  individual  prophy- 
laxis is  to  keep  away  from  infected  localities,  and  from  those  places 
where  the  disease  is  epidemic— *.  g.,  Havana,  Veracruz,  Rio  Janeiro — 
during  the  season  of  its  prevalence.  Very  many  lives  have  been  sacri- 
ficed by  a  misplaced  confidence  in  the  protection  which  courage  is  sup- 
posed to  afford  against  this  disease.  "I  am  not  afraid,"  says  the  mer- 
chant whose  business  calls  him  to  an  infected  city,  or  the  sea-captain 
who  wishes  to  obtain  a  cargo  of  sugar  in  Havana  during  the  summer 
months.  But  not  being  afraid  does  not  prevent  such  persons  from 
being  attacked.  And  the  mortality  in  Havana  among  sailors  from 
northern  latitudes  is  very  great.  There  is  a  tendency  in  places  where 
the  disease  is  endemic  to  underrate  its  malignity,  and  to  ascribe  every 
fatal  case  to  some  fault  nn  the  part  of  the  unfortunate  victim  or  his  at- 
tendants. H<-  was  'frightened  to  death."  or  "was  not  propcrlv  nursed." 
or  he  was  "imprudent,"  etc.,  etc.  The  mortality  is  no  doubt  largely 
influenced  by  these  secondary  causes,  but  yellow  fever  is  a  malignant 
disease,  which  under  the  most  favorable  circumstances  is  very  fatal  to 
unacclimated  strangers  within  the  limits  of  its  endemic  prevalence, 
and  which  in  its  epidemic  extension  in  new  territory  often  claims  from 
30  to  35  per  cent.,  or  even  more,  of  those  who  fall  sick,  as  its  victims 


38  DISINFECTION. 

This  being  the  case,  we  repeat  our  advice  to  all  those  whose  duty  does 
not  require  them  to  stay  on  the  field  of  battle,  to  make  an  orderly  re- 
treat to  some  place  of  safety. 

The  precautions  relating  to  food  and  to  personal  habits  do  not  differ 
materially  from  those  recommended  in  the  case  of  cholera.  The  diet 
should  be  simple,  and  excesses  should  be  avoided.  Less  care  will  be 
necessary  with  reference  to  the  use  of  fruits  and  vegetables — indeed, 
they  are  rather  to  be  recommended,  as  better  suited  than  animal  food 
to  the  warm  latitude  in  which  this  disease  prevails.  Constipation 
should,  above  all  things,  be  avoided ;  and  if  there  is  evidence  that  the 
functions  of  the  liver  or  kidneys  are  imperfectly  performed,  suitable 
medication  should  be  resorted  to. 

There  is  no  special  danger  from  the  use  of  water,  if  it  is  from  a  source 
which  insures  it  from  contamination  with  organic  impurities.  Spirit- 
uous liquors,  if  used  at  all,  should  be  taken  in  great  moderation. 
Nothing  is  more  likely  to  develop  an  attack  than  alcoholic  excesses, 
and  the  habitual  drunkard  is  almost  doomed  to  death  if  he  falls  sick 
with  this  disease.  Exposure  to  the  direct  rays  of  the  sun,  excessive 
fatigue,  and  venereal  excesses  are  all  predisposing  causes  which  it  is 
within  the  province  of  individual  prophylaxis  to  avoid.  Exposure  to 
the  night  air,  and  especially  sleeping  out  of  doors  near  the  ground,  is 
recognized  by  experienced  physicians  in  yellow  fever  regions  as  an  in- 
vitation to  an  attack.  Great  care  should  be  taken  to  avoid  chilling 
of  the  body,  and  it  is  well  to  sleep  as  far  from  the  ground  as  possible. 
The  Creoles  of  Louisiana  and  of  the  West  Indies  generally  insist  upon 
closing  the  windows  of  a  sleeping-room  at  night. 

The  mortality  among  natives  of  tropical  climates,  and  especially 
among  those  whose  habits  are  good,  and  who  are  accustomed  to  a 
frugal  mode  of  life,  is  very  much  less  than  among  the  natives  of  north- 
ern latitudes,  when  these  come,  without  any  previous  "acclimation," 
within  the  influence  of  the  yellow  fever  poison.  Those  who  are  habit- 
uated to  life  in  the  extreme  South  enjoy  a  certain  immunity  from  the 
effect  of  the  poison,  which  is  shown  by  a  lower  death-rate  rather  than 
any  exemption  from  being  attacked.  One  attack  of  this  disease,  as  a 
rule,  confers  immunity  from  a  subsequent  attack. 

Individual  prophylaxis  in  an  infected  city  will  include  the.  avoidance 
of  those  localities  which  give  special  evidence  of  being  infected,  and 
especial  care  not  to  visit  such  localities  at  night. 

The  liberal  use  of  disinfectants  in  cesspools  and  water-closets,  and  a 
perfect  state  of  sanitary  police  in  and  around  the  premises,  will  consti- 
tute a  most  important  part  of  the  precautionary  measures  which  every 
individual  should  take  for  his  own  protection  and  that  of  his  family. 
A  state  of  mental  equilibrium,  and  an  intelligent  appreciation  of  the 


DISINFECTION.  39 

special  circumstances  in  which  he  is  placed,  and  of  the  various  meas- 
ures of  prophylaxis  heretofore  indicated,  will  enable  an  individual  to 
look  the  facts  fairly  in  the  face,  and  to  be  goverened  by  the  light  of 
reason  and  of  science.  Unfortunately  it  too  often  happens,  among  the 
ignorant  and  degraded,  that  a  spirit  of  bravado,  attended  with  a  neg- 
lect of  the  simplest  sanitary  precautions,  and  a  disposition  to  deny  the 
presence  of  the  dreaded  foe,  prevails  during  the  earlier  stages  of  an 
epidemic,  and  that  this  is  followed  by  a  disorderly  stampede  and  a  dis- 
graceful neglect  of  the  sick,  when  the  presence  and  malignant  nature 
of  the  pestilence  are  recognized. 

Smallpox.  This  disease  is  contracted  by  exposure  to  emanations 
from  the  body  of  the  sick,  or  from  articles  which  have  been  in  use  by 
them,  or  exposed  in  their  vicinity.  There  is  no  evidence  that  the  small- 
pox poison  multiplies  external  to  the  human  body,  and  the  indications 
for  prophylaxis  are  therefore  quite  different  from  those  already  given 
for  cholera  and  yellow  fever.  One  may  eat  what  he  pleases,  and  wal- 
low in  filth,  when  smallpox  is  prevailing,  without  contracting  the  dis- 
ease, so  long  as  he  keeps  away  from  the  sick,  and  is  not  brought  in  con- 
tact with  any  article  infected  by  them.  In  this  disease,  however,  as  in 
the  infectious  diseases  generally,  previous^personal  habits  will  greatly 
influence  the  result  when  exposure  does  occur ;  and  the  disease  is  more 
fatal  to  the  victims  of  alcoholism,  to  those  who  are  poorly  nourisl 
and,  in  general,  to  those  whose  vitality  is  reduced  by   i  >  to 

noxious  effluvia  from  putrefying  material,  by  living  in  overcrowded  and 
ill-ventilated  apartments,  etc. 

As  it  is  now  the  universal  practice  to  isolate  smallpox  patients  as 
soon  as  the  disease  is  recognized,  the  danger  of  coming,  accidentally. 
in  contact  with  them  is  not  great.     There  is  but  little  danger  of  inl 
tion  from  passing  within  a  few  yards  of  a  patient  with  smallpox  in  the 
open  air.  or  from  passing  a  building  in  which  c;  under  tr< 

ment.     Unprotected  persons  who  enter  the  sick-room  ai 
extremely  liable  to  contract  the  disease;  and  the  inf  materia] 

given  off  from  the  patient's  body  clings  mosl 

to  clothing,  etc..  and  may  give  rise  to  an  attack-  after  many  monl 
unless  destroyed  by  disinfection. 

It  is  evident,  then,  that  individual  prophylaxis  will  include  ' 
ano  which  have  been  occupied  by  the  side,  and  of  art i 

used  by  them,  unless  there  is  a  ceii  linty  that  t!  i 
disinfected,     it    is  probable  that   an   unprotected   person,   who  f< 
obliged,  for  special  reasons,  to  enter  th  iom,  ma)  in 

fection  by  the  use  of  an  air  filter  pi  the  mouth  and   I 

This  should  be  constructed  on  the  principal  oi  the  "Tyndal 
in  which  all  inspired  air  is  made  to  pass  through  a 


40  DISINFECTION, 

ding,  which  arrests  suspended  particles.  It  would  be  necessary  im- 
mediately on  coming  out  of  the  room  to  burn  the  cotton  filter,  to  bathe 
the  hands  and  face  in  a  disinfecting  solution,  and  to  change  the  outer 
clothing. 

It  is  a  general  rule  in  regard  to  infectious  diseases  that  those  who  are 
necessarily  exposed  to  them  should  take  the  precaution  of  not  going 
into  the  sick-room  with  an  "empty  stomach,"  or  in  a  condition  of  ex- 
haustion from  any  cause.  A  cup  of  coffee,  or  a  glass  of  wine  and  a 
cracker,  may  be  taken  if  a  considerable  interval  has  elapsed  since  the 
last  regular  meal. 

It  is  well-known  that  against  smallpox  we  have  a  special  measure  of 
prophylaxis,  which  has  restricted  the  ravages  of  this  disease  within  the 
limits  which  are  left  to  it  by  carelessness  in  regard  to  the  application  of 
tli  is  measure,  or  ignorance  of  its  value.  Since  the  famous  discovery  by 
Jenner,  vaccination  has  become  the  prophylactic  par  excellence. 

The  immunity  conferred  by  vaccination  is,  as  a  rule,  complete ;  but 
there  are  exceptions  to  this  rule,  and  vaccinated  persons  occasionally 
suffer  from  a  modified  form  of  the  disease.  The  statistics  of  the  Lon- 
don smallpox  hospital  show  that  the  mortality  among  unvaccinated 
persons  received  into  that  hospital  with  smallpox,  is  35.55  per  cent. ; 
while  the  mortality  among  vaccinated  persons  is  less  than  7  per  cent. 
No  doubt  a  large  proportion  of  the  cases  of  post-vaccinal  smallpox 
might  have  been  prevented  by  revaccination. 

It  is  now  recognized  that  the  protective  influence  of  vaccination  is  not 
always  of  a  permanent  character,  and  children  who  have  been  success- 
fully vaccinated  in  infancy  should  be  revaccinated  when  they  reach  the 
age  of  puberty,  or  sooner,  if  smallpox  is  prevailing  in  the  neighbor- 
hood. The  operation  is  so  trifling  that  it  is  customary  to  vaccinate  old 
and  young,  with  the  exception  of  those  who  have  been  successfully 
vaccinated  within  a  year  or  two,  whenever  an  outbreak  of  smallpox 
occurs.  This  practice  is  to  be  recommended,  but  when  the  operation 
has  been  performed  in  a  proper  manner,  with  virus  which  is  known  to 
be  reliable,  it  is  folly  to  insist  upon  a  frequent  repetition  of  the  vaccina- 
tion, because  "it  didn't  take."  If  the  first  vaccination  has  been  com- 
pletely successful,  a  perfect  result  from  revaccination  is  not  usually  ob- 
tained ;  and  the  fact  that  no  result  is  obtained  must  be  taken  as  evidence 
that  the  person  is  protected.  The  prophylactic  value  of  vaccination 
practiced  after  exposure  to  smallpox  has  been  demonstrated,  and  one 
who  is  not  entirely  certain  that  he  is  protected  by  a  recent  successful 
vaccination  will  do  well  to  resort  to  this  important  prophylactic  meas- 
ure at  once,  if  he  has  reason  to  suspect  that  he  has  been  exposed  to 
smallpox. 


DISINFECTION.  41 

Scarlet  Fever.  In  this  disease,  as  in  smallpox,  the  poison  is  given 
off  from  the  bodies  of  the  sick,  and  is  not  reproduced  independently  of 
them.  As  we  have  no  knowledge  of  any  means  of  protection  corre- 
sponding with  vaccination,  prophylaxis  consists  solely  in  keeping  out 
of  the  reach  of  infection  by  the  sick,  or  by  articles  infected  by  them. 

The  sick  person  may  communicate  the  disease  during  the  whole 
period  of  his  illness  and  convalescence, — a  period  which  often  extends 
to  five  or  six  weeks,  or  even  longer  than  this.  Infected  clothing,  which 
has  been  packed  away  for  months,  may  communicate  the  disease ;  and 
there  are  numerous  instances  on  record  of  its  transmission  to  children 
at  a  distance  from  the  sick,  by  healthy  persons  who  have  recently  come 
in  contact  with  scarlet  fever  patients.  The  lower  animals,  and  espe- 
cially pet  cats  and  dogs  which  may  have  visited  the  sick-room  unno- 
ticed, or  which  are  thoughtlessly  given  to  convalescent  children  for 
their  amusement,  constitute  a  great  source  of  danger.  Persons  who 
have  suffered  a  attack  of  the  disease,  or  who  have  but  little  suscepti- 
bility to  it,  may  have  a  slight  sore  throat  as  a  result  of  exposure  to  the 
scarlet  fever  poison,  and  may  communicate  the  disease  in  its  more 
severe  form  to^inprotected  children.  One  great  difficulty  in  arresting 
the  progress  of  an  epidemic  by  isolation  of  the  sick  and  disinfection, 
results  from  the  fact  that  these  slight  and  often  unrecognized  cases  are 
frequently  allowed  full  liberty. 

Infection  has  been  traced  to  milk  which  had  been  standing  in  the 
sick-room,  or  to  the  same  liquid  which  had  become  infected  in  a  dairy 
where  scarlet  fever  had  prevailed,  and  where  recent  convalescents  were 
permitted  to  milk  the  cows. 

All  of  the  facts  point  to  a  most  rigid  exclusion  of  susceptible  children 
from  every  possible  source  of  infection.  The  susceptibility  of  adults  is 
very  much  less,  and,  when  attacked,  they  usually  have  the  disease  in  a 
mild  form.  But  their  responsibility  extends  far  beyond  the  point  of 
avoiding  the  sick  for  their  own  protection.  Those  who  are  associated 
with  susceptible  children  have  no  right  under  any  circumstances  to 
visit  the  room  of  a  scarlet  fever  patient  without  taking  the  most  thor- 
ough precautions  with  regard  to  the  disinfection  of  their  person  and 
clothing  immediately  upon  leaving  it  ;  and  even  with  these  precautions, 
such  a  visit  cannot  be  justified  when  it  is  made  simply  out  of  curiosity 
or  friendship.  ( )nly  those  who  are  in  attendance  upon  the  siek  should 
be  allowed  in  the  sick-room,  and  they  must  he  regarded  U  infected 
persons,  who  are  not  to  he  permitted  to  come  in  contact  with  unpro- 
1  children  while  they  are  engaged  in  this  duty. 

Piphtheria.  'I  his  is  a  i!im-«<-c  in  which  the  infectious  material  it 
given  off  from  the  surfaces  affected,  and  not  from  the  general  surface 
of  the  body.     As  the  usual  seat  of  the  disease  is  the  throat  and  the  iusal 


42  DISINFECTION. 

mucous  membrane,  it  is  the  discharges  from  these  surfaces  which  are 
especially  dangerous.  Although  adults  are  much  less  susceptible  to 
the  disease  than  children,  there  have  been  numerous  instances  in  which 
they  have  contracted  diphtheria  by  the  accidental  reception  of  a  bit  of 
infectious  material  directly  into  the  fauces.  This  is  especially  liable  to 
occur  during  the  operation  of  tracheotomy ;  and  several  physicians  have 
lost  their  lives  in  this  way,  in  their  efforts  to  save  those  of  their  patients 
by  aspirating  through  the  tracheotomy  tube.  It  seems  extremely  prob- 
able that  the  diphtheria  bacillus  is  capable  of  increase  independently 
of  the  sick,  in  damp,  foul  places,  such  as  sewers,  damp  cellars,  and  es- 
pecially under  old  houses  in  which  the  floors  come  near  the  surface  of 
the  ground,  leaving  a  damp,  ill-ventilated  space.  At  all  events,  the 
disease  often  clings  to  such  houses  in  spite  of  the  application  of  the 
usual  means  of  disinfection.  There  is  no  doubt  as  to  the  influence  of 
bad  hygienic  conditions  in  maintaining  the  infection  when. the  disease 
has  been  introduced,  and  it  is  possble  that  such  conditions  may,  in  cer- 
tain cases,  originate  it. 

Insufficient  nourishment,  the  malarial  poison,  aricl^  insanitary  sur- 
roundings are  predisposing  causes  to  the  disease.  Those  suffering 
from  scarlet  fever,  measles,  whooping-cough,  and  tuberculosis  are  also 
especially  liable  to  be  attacked.  As  in  the  case  of  scarlet  fever,  mild 
cases,  which  is  the  absence  of  others  more  pronounced  it  would  be 
difficult  to  recognize  as  true  diphtheria,  may  give  rise  to  malignant 
diphtheria  in  more  susceptible  individuals,  or  in  those  whose  vital  re- 
sisting power  is  reduced  by  any  of  the  causes  mentioned. 

Prophylaxis  will  demand  complete  non-intercourse  with  the  sick, 
avoidance,  of  infected  localities,  and  care  to  exclude  all  persons  and  arti- 
cles coming  from  such  houses  from  contact  with  yourself  or  children. 
The  disease  is  often  spread  by  thoughtless  persons  who  visit  the  sick- 
room, and  even  kiss  the  infected  patients,  and  then,  without  any  pre- 
cautions in  the  way  of  disinfection,  fondle  healthy  children  in  other 
places,  and  perhaps  transmit  by  a  kiss  the  infectious  material  which  has 
adhered  to  their  lips.  The  possibility  of  transmission  by  pet  animals 
is  also  to  be  borne  in  mind. 

It  has  been  demonstrated  by  the  bacteriologists  connected  with  the 
health  departments  in  our  large  cities  that  the  diphtheria  bacillus  is 
often  found  in  the  throats  of  patients  convalescent  from  this  disease 
for  three  or  four  weeks  after  the  attack,  and  exceptionally  for  a  much 
longer  time  than  this.  The  time  when  it  will  be  safe  for  a  convalescent 
from  this  disease  to  associate  with  susceptible  children  can  therefore 
not  be  determined  with  certainty  except  by  a  bacteriological  examina- 
tion made  by  an  expert. 


DISINFECTIi 

The  most  important  method  of  prophylaxis  for  children  who  are  una- 
voidably exposed  to  the  danger  of  infection  is  the  use  of  protective  in- 
oculations by  sub-cutaneous  injection,  of  the  diphtheria  antitoxin. 
The  value  of  this  method  has  been  amply  and  repeatedly  demonstrated 
in  children's  hospitals,  in  asylums,  and  in  private  practice.  The  pro- 
tection afforded  by  such  inoculations  is  not  permanent,  and  probably, 
as  a  rule,  does  not  last  longer  than  a  few  weeks. 

Tuberculosis.  Scientific  researches  have  demonstrated  that  tubercu- 
lar consumption  is  an  infectious  disease,  and  that  the  sputa  of  those 
affected  with  it,  injected  into  susceptible  animals,  reproduces  in  them 
the  same  disease.  This  sputum  is  therefore  infectious  material,  and 
should  be  destroyed  by  burning,  or  by  the  use  of  chemical  disinfectants. 
There  would  be  little  danger  of  infection  from  the  moist  masses  of 
sputum,  but  in  a  desiccated  condition  this  material  is  liable  to  reach  the 
lungs  of  susceptible  individuals,  and  to  induce  the  disease. 

It  is  well  known  that  there  is  a  great  difference  in  susceptibility 
to  pulmonary  consumption,  and  that  in  certain  families  this  disease 
carries  off  one  member  after  another,  while  it  is  unknown  in  other  fam- 
ilies. Those  who  have  this  hereditary  predisposition  should  pay  spe- 
cial attention  to  individual  prophylaxis.  They  should  avoid  intimate 
association  with  consumptive  persons,  should  live  under  the  best 
hygienic  conditions,  in  dry,  well-ventilated  apartments,  and  should  se- 
lect an  occupation  which  will  keep  them  in  the  open  air,  rather  than  one 
which  keeps  them  confined  to  the  house.  Above  all,  they  should  avoid 
the  respiration  of  an  atmosphere  loaded  with  organic  impurities,  or  with 
irritating  inorganic  particles — dust  of  various  kinds.  Out  of  door  life 
on  the  high  and  dry  plains  in  the  center  of  tin-  continent,  or  in  the 
mountains,  will  in  most  instances  enable  them  to  overcome  the  predis- 
position, if  commenced  before  infection  and  the  resulting  tubercular 
lesions  have  occurred. 

Those  who  are  engaged  in  occupations  which  require  •'  pass 

some  hours  each  day  in  an  atmosphere  loaded  with  dust  will  do 

rator  for  filtering  the  suspended  particles  from  the  air 

it  is  demonstrated  that,  independently  of  hereditary  predisposition,  the 
respiration  of  such  an  atmosphere  predisposes  to  tubercular  d 
the  lungs. 

Typhoid  Fever.     [n#this  •'  -  in  cholera,  the  infectious  agent  is 

contained  in  the  alvine  discharges  of  the  sick.     In  the  int< 
preservation  as  well  as  in  that  ->f  the  public  good,  every  individual  who 
has  charge  of  cases  should  see  that  the  evacuatii  ma  from  th< 

thoroughly  disinfected  before  they  are  thrown  out. 

The  drinking  of  water  contaminated  with  such  inf< 

is  recognized  as  a  very  frequent  I  'inn  ;  and  individual  • 

phylaxis  demands  an  intelligi 


44  DISINFECTION. 

a  supply  of  drinking-water  is  obtained  for  personal  or  family  use.  If 
there  is  the  least  reason  to  suspect  that  this  supply  may  be  contaminated 
by  typhoid  material,  or  if  it  contains  an  undue  amount  of  organic  im- 
purities, it  should  be  rejected  entirely,  or  boiled  shortly  before  it  is 
used. 

Typhoid  epidemics  have  in  several  instances  been  traced  to  using 
milk  which  had  been  contaminated  by  infected  water,  added  to  it  di- 
rectly, or  used  at  the  dairy  for  washing  the  vessels  containing  it.  The 
remedy  in  this  case  is  to  verify  the  purity  of  the  source  of  supply  of  all 
milk  used  for  drinking,  or  to  boil  it  immediately  before  it  is  used. 

The  water  of  wells  located  within  the  limits  of  a  city  or  village  should 
not,  as  a  rule,  be  used  for  drinking  purposes,  for  the  soil  is  almost  cer- 
tain to  be  polluted ;  and  it  often  occurs  that  the  contents  of  privy  vaults 
and  cesspools  pass  into  the  same  porous  stratum  of  sand  or  gravel  from 
which  the  well-water  is  obtained,  or  that  surface  drainage  finds  its  way 
into  shallow  wells.  It  will  be  necessary,  also,  to  regard  with  suspicion 
the  water  of  small  streams  and  ponds  which  are  so  situated  that  they 
may  receive  the  drainage  from  collections  of  filth  upon  their  margin. 

Next  to  impure  water  we  must  place  impure  air  as  a  factor  in  the  eti- 
ology of  typhoid  fever.  There  is  good  reason  to  believe  that  the  germs 
of  the  disease  may  be  carried  by  the  foul  gases  which  are  given  off  from 
sewers,  privies,  etc.,  when  these  become  infected,  and  that  the  disease 
may  be  induced  by  the  respiration  of  such  a  contaminated  atmosphere. 
At  all  events,  the  breathing  of  a  vitiated  atmosphere,  and  insaintary  sur- 
roundings generally,  constitute  predisposing  causes  which  should  ba 
avoided. 

There  can  be  no  doubt  that  typhoid  fever,  cholera,  and  other  infec- 
tious diseases  are  not  infrequently  transmitted  through  the  agency  of 
insects,  and  especially  of  flies.  These  domestic  pests  are  likely  to  light 
upon  the  excreta  of  persons  suffering  from  infectious  diseases,  if  it  is 
left  standing  in  receptacles  of  any  kind,  or  is  thrown  without  previous 
disinfection  upon  the  ground  or  in  shallow  pits.  From  these  foul 
places,  with  their  feet  and  legs  soiled  by  contact  with  material  contain- 
ing typhoid  or  cholera  germs,  they  may  fly  to  a  neighboring  kitchen 
and  there  light  upon  articles  about  to  be  served  as  food,  or  may  fall  into 
the  milk  jug,  etc.  This  mode  of  infection  is  to  be  prevented  by  clean- 
liness, prompt  disinfection  of  all  infectious  material  and  the  use  of  suit- 
able screens  to  exclude  these  carriers  of  infection  from  human  habita- 
tions. 

In  typhoid  fever,  as  in  yellow  fever  and  cholera,  depressing  mental 
emotions,  such  as  grief,  despondency,  or  fear,  and  physical  exhaustion 
from  excessive  fatigue,  insufficient  food,  etc.,  are  predisposing  causes 
which  may  induce  an  attack  in  the  presence  of  the  infectious  agent. 


DISINFECTION.  45 

Malarial  Fevers.  One  of  the  latest  and  most  important  achieve- 
ments of  scientific  medicine  is  the  demonstration  that  malarial  fevers 
are  due  to  infection  by  a  microscopic  parasite  which  is  found  in  the 
blood,  and  that  the  usual  way  in  which  such  fevers  are  contracted  is  by 
the  stings  of  infected  mosquitoes.  Fortunately  not  all  mosquitoes  are 
infected  with  this  parasite.  A  certain  species,  found  in  marshy  regions 
in  tropical  or  sub-tropical  countries,  has  been  proved  to  be  chiefly  con- 
cerned in  the  transmission  of  these  fevers  to  man.  The  evident  meas- 
ures of  prophylaxis  consists  in  avoiding  the  marshy  regions  where 
these  noxious  insects  abound,  and  especially  at  night,  when  they  are 
most  active ;  or  in  the  use  of  mosquito  bars  and  other  means  of  protec- 
tion from  the  stings  of  these  infected  mosquitoes  when  in  the  vicinity 
of  the  places  infected  by  them. 

In  addition  to  these  precautions  it  is  best  to  take  from  five  to  ten 
grains  of  quinine  daily  as  an  antidote  to  infection,  when  exposed  in  a 
decided  malarious  region.  In  giving  these  directions  it  must  be  re- 
membered that  they  refer  only  to  the  typical  malarial  fevers  which  are 
contracted  in  marshy  regions.  The  so-called  "malaria"  of  cities  is,  as  a 
rule,  due  to  entirely  different  causes. 

Concluding  remarks.  This  chapter  might  be  greatly  extended,  but, 
having  passed  in  review  the  principal  measures  of  individual  prophy- 
laxis against  those  infectious  diseases  which  are  most  fatal,  we  shall 
not  dwell  upon  precautions  to  be  taken  in  other  contagious  diseases, 
such  as  measles  and  whooping-cough.  These  precautions  will  not 
differ  from  those  already  recommended  in  the  cases  of  smallpox  and 
scarlet  fever.  So,  too,  in  regard  to  the  infectious  skin  diseases.  These 
are  communicated  by  personal  contact,  and  rarely  occur  except  among 
those  who  neglect  personal  cleanliness,  as  well  as  other  Military  laws. 
Soap  and  water  will  generally  suffice  for  individual  prophylaxis.  By 
avoiding  filthy  persons  as  well  as  filthy  places,  the  danger  of  contract- 
ing these  and  certain  other  unmentionable  infectious  diseases  will  be 
reduced  to  a  minimum. 


1 
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